What if the USA enters WW2 in September 1939?

[Colin Williams]

Assuming for some bizarre reason (say subliminal mind control messages broadcast by the French and British through the Jack Benny radio show) the American public are bright enough to see the global danger posed by Nazi Germany, toss off the blinders of isolationism, and push Congress and FDR to declare war on September 3, 1939.

 

What does the US Army (including the Air Corps) have to deploy to Europe on that date?

 

What conceivably could the US Army build up to in France by May, 1940?

 

Could those additional forces have made any difference to the campaign of 1940?

[Mk 1]

Assuming for some bizarre reason (say subliminal mind control messages broadcast by the French and British through the Jack Benny radio show) the American public are bright enough to see the global danger posed by Nazi Germany, toss off the blinders of isolationism, and push Congress and FDR to declare war on September 3, 1939.

An interesting enough question. Better than many of our "what if's" to my observation. Not that it was likely, but exploring the question itself can lead to an expanded understanding of where the US actually was, militarily, in 1939.

 

What does the US Army (including the Air Corps) have to deploy to Europe on that date?

Almost nothing. The US Army is smaller than the Portuguese Army, and is far behind the Polish Army in modern weaponry. About the only tanks in actual service are a few totering post-WW1 production US license built Renault Ft-18s. Even the M2 light and M2 medium tanks are just starting to come to production IIRC.

 

The closest the US Army would have to a mechanized force would be horse cavalry units that could be transported by truck/trailer to the front.

 

The USAAC at this time is in the midst of re-equipping its pursuit squadrons with "modern" P-35s and P-36s, although there are probably still a few squadrons operating P-26 Peashooters. The P-36 doesn't stack up like a star compared to a Bf-109, but the French actually did OK with them in 1940, particularly when matched against a -109d that was the more common varient in 1939/40. The P-35 is somewhat further behind, but still really no worse off than the MS-406 that forms the bulk of the FAF in May of 1940.

 

The P-39 and P-40 are not yet available, and won't be in time for the May 1940 campaign.

 

In terms of bombers the USAAC is in better shape than most of the other allies. The B-18 should not be dismissed versus some of the Polish, French, or British bombers in service in 1939. And the more impressive Boston, Maryland, and B-17 are available for production to ramp up in time for participation in the May 1940 struggle.

 

Could those additional forces have made any difference to the campaign of 1940?

The US Army was a cadre. It would take at least two years to turn the US Army into a fighting force of a scale that mattered for continental Europe, and that assumes that the weapons systems it would need were ready for production. Rifles were, artillery was, but the automotive components, most notably the tanks and AT guns were not, and would not be in time for the May 1940 campaign in France. A few divisions of foot-bound riflemen would not have lead to anything other than US participation in the Dunkirk operations (from the beach side). The US Army could not have mustered more.

 

The one strength that the US had in 1939 was the USN. The USN was a real and ready fighting force. The problem is that there is no clear path for a substantial increment in allied naval forces to make a difference in most of the campaigns of 1939 and 1940. The one fight I could see going down differently was Norway. If the USN had combat forces placed in the UK by the spring of 1940, the whole German move into Norway may have been averted, hampered, or defeated. Would that have thrown enough of a monkey-wrench into Hitler's doings to forestall the May romp across France?

 

Or so I am expecting. Will be interested to read more from the rest of the gang.

 

-Mark 1

[Sardaukar]

Even if USA would not participate land combat etc. that much, it's economical output would have been considerable after gearing up to wartime production.

 

BTW, how many fighter pilots they could have lended to RAF in 1940 ? AFAIK, one of the difficulties RAF had then was not that much about lacking fighter planes anymore but the depletion of pilot pool. Even 10-20% increase to RAF fighter numbers would have caused significant problems to Luftwaffe to bomb UK.

 

And more so if USN would have gotten fully into protecting supply convoys, U-boats would have had considerably rougher times compared to "Happy Times".

[seahawk]

The Navy could contribute a lot. Norway would be impossible imho for the germans, as would be any planing for Sea Lion, should the battle of France still go the historic way, which I would believe. Without Sea Lion, the Battle of Britian might become a Battle of France, with the UK/US AirForces trying to win control over mainland France.

[Gabe]

There would be no chance Britain would surrender and France would be less likely to. If they could hang on for 2 years the tide would turn with American industrial output. Hitler would have to take this into account, and German victory aims in the Western front will probably have to be less ambitious.

[Colin Williams]

I found the text of Gen. Marshall's biennial report to Congress on the state of the Army, covering July 1, 1939 to July 1, 1941. Looking at 1939, I get the impression that there were only 3 infantry divisions anywhere near full strength, so I suppose it is possible that they could have been brought up to strength and deployed to France along with a tank unit of some sort (battalion?, brigade?, regiment?). An interesting question would be whether the Army would try to send a cavalry division also.

http://www.ibiblio.org/hyperwar/USA/COS-Bi...Biennial-1.html

 

[Manic Moran]

I'm reading that diagram as showing the three 10,000 man divisions to be at about 30% strength.

 

NTM

[Sardaukar]

I thik we could safely conclude that land contribution of USA was out of question in 1939. USN was in quite good shape..anyone have figures how air units would have been ?

 

I think it's also safe to assume that contribution of USA would have been mainly industrial, naval and air power during first 12 months of war.

Edited December 21, 2007 by Sardaukar

[Colin Williams]

I thik we could safely conclude that land contribution of USA was out of question in 1939. USN was in quite good shape..anyone have figures how air units would have been ?

 

I think it's also safe to assume that contribution of USA would have been mainly industrial, naval and air power during first 12 months of war.

 

It depends on how you handle the manpower and whether any equipment is available. For example, there were more than enough men in GHQ reserve, Overseas garrisons and Overhead to fill up the three divisions, but doing that potentially cripples the effort to build up a larger force for a long war. In the 1939-40 timeframe the Allies were planning for a long war, so I expect most of the active Army and existing National Guard would have been used as cadres for new divisions. At the same time, I imagine there would have been a lot of pressure to send some sort of token expeditionary force, as was done in 1917. Perhaps 2 divisions go to France in the winter of 1939-40, with a promise of more in the summer or fall?

 

Of course the worst case scenario would be the deployment of a couple of underequipped divisions and a skeletal tank force in 1940, only to lose them in the campaign for France.

 

BTW, who would be most likely to get the job of commanding the AEF in 1939? I imagine it would have to be someone of stature like Marshall or MacArthur, or perhaps if the initial force is small someone like Stillwell or Krueger.

[Gregory]

I'm reading that diagram as showing the three 10,000 man divisions to be at about 30% strength.

 

NTM

No - because that would lead to the others being 3500 man divisions at about 20% strength - and there was no such thing as a 3500 man division in US TO&E. What was the 2nd cavalry division - something in the Phillipines?

[Mk 1]

I'm reading that diagram as showing the three 10,000 man divisions to be at about 30% strength.

I think that it is showing 9 Infantry Divisions with an establishment of 22,000-25,000 men. 4 are at about 40%, and the rest at about 15%.

[DB]

In terms of land forces, how many US troops could have been expected to be in France in May 1940, and would they have had any influence on the disposition of forces by Gamelin, or later on the defensive tactics of Weygand?

[Sardaukar]

In terms of land forces, how many US troops could have been expected to be in France in May 1940, and would they have had any influence on the disposition of forces by Gamelin, or later on the defensive tactics of Weygand?

 

I think we'd be talking only about 2-3 divisions max..sort of AEF Corps maybe. I don't think there were much chance to field more troops in Europe before 1941 by US. That'd be just a drop in sea, maybe good drop, but just too little to affect the outcome.

 

On the other hand, Germany would be hard pressed to successfully invade Norway. Denmark yes, but Norway would be very very difficult with RN, USN and French etc. navies. That would have changed things a lot in Scandinavia. For example, Germany did need iron ore from Sweden and securing that was one of the primary reasons for invasion of Norway. It'd be totally new ballgame up there...I think if Allied would have landed to Norway, in that case, Germans would have had to invade Sweden and possibly Finland to secure the mines (they could still count having naval and air superiority in Baltic).

Edited December 22, 2007 by Sardaukar

[Olof Larsson]

I think we'd be talking only about 2-3 divisions max..sort of AEF Corps maybe. I don't think there were much chance to field more troops in Europe before 1941 by US. That'd be just a drop in sea, maybe good drop, but just too little to affect the outcome.

 

On the other hand, Germany would be hard pressed to successfully invade Norway. Denmark yes, but Norway would be very very difficult with RN, USN and French etc. navies. That would have changed things a lot in Scandinavia. For example, Germany did need iron ore from Sweden and securing that was one of the primary reasons for invasion of Norway. It'd be totally new ballgame up there...I think if Allied would have landed to Norway, in that case, Germans would have had to invade Sweden and possibly Finland to secure the mines (they could still count having naval and air superiority in Baltic).

 

The invasion of Norway was an extremely risky operation.

It was based on the premesis, that the norwedians wouldn't resist

and there was no reserves avialable (the operation used the "left-overs" from "Fall Gelb".

 

In the first few days, very small differences could have turned the invasion to a failure.

If the norwegians hadn't sent that rifle-company to the wrong (eastern) side of the Oslofjord

to take care of the Blücher survivors,

they might have prevented the germans from taking Fornebu airport (on the western side of the Oslofjord)

on the on the 9th, and thereby forcing the norwegian goverment to evacuate north)

Even a few more beltboxes for the mashinegun platon on Fornebu, might have ashived the same result.

 

The same might have happend if the danes have held out (or denied the Luftwaffe the use of their airfields) for a day or two.

 

But after the first critical days, the germans had a clear upper hand.

More ships after those few days probably wouldn't change much as far as the outcome of the campain goes,

unless the allies could cling on to the northern half of the country.

 

The germans would still dominate the waters between Denmark and Norway,

so the german troops would continue to come in.

 

More ships in the Northsea prior to the 9th of april, might have led to

parts of the first german wave to be intercepted

and that might have changed the outcome completely.

 

If forinstance Gruppe II (Hipper and 4 destroyers heading to Trondheim with parts of the 138th mountain infantry regiment)

was intercepted prior to the 9th, the only germans tropps in the northern 2/3 of Norway,

would be i Narvik (and those troops was historicaly beaten by norwegian/brittish/french/polish troops)

and the allies could land directly in the Trondheim port.

 

More ships could obviously cause the germans even more losses of ships

(making the german fleet for Seelöwe even more inadequate)

 

If the allies could win in (or initially cling on to parts of) Norway, then the war might take a different turn.

Sweden wouldn't be locked in by the germans, so our options would be far better.

 

If Sweden would join the allies, Bomber Command (and later USAAF) could operate from bases

with haft the distance (compared to brittish bases) to Berlin, increasing the bombloads that could be carried

and making fighter escort all the way to Berlin available earlier.

 

Furthermore many of the submarine shipyards and Peenemünde

would be far closer to allied airbases.

 

 

In what shape was the USMC in 1940?

To what extent could they have contributed to the allied effort in Norway?

[Jim Martin]

The invasion of Norway was an extremely risky operation.

In what shape was the USMC in 1940?

To what extent could they have contributed to the allied effort in Norway?

 

In 1939 I don't believe the USMC was equal to even a full division. We had a regiment, the 4th Marines, in China, and I'm not sure what else we had of even regimental strength. Maybe a regiment on each coast? Ken Estes would have more info.

[John_Ford]

No - because that would lead to the others being 3500 man divisions at about 20% strength - and there was no such thing as a 3500 man division in US TO&E. What was the 2nd cavalry division - something in the Phillipines?

 

 

 

Not quite, sad ending for what sounded like a pretty good unit. They were used for Cadre for a number of units and when it came time for them to deploy, they were turned into service troops.

 

 

http://en.wikipedia.org/wiki/2nd_Cavalry_D...(United_States)

[Archie Pellagio]

name='Olof Larsson' date='Sat 22 Dec 2007 1933' post='524793']The invasion of Norway was an extremely risky operation.

It was based on the premesis, that the norwedians wouldn't resist

and there was no reserves avialable (the operation used the "left-overs" from "Fall Gelb".

 

In the first few days, very small differences could have turned the invasion to a failure.

If the norwegians hadn't sent that rifle-company to the wrong (eastern) side of the Oslofjord

to take care of the Blücher survivors,

they might have prevented the germans from taking Fornebu airport (on the western side of the Oslofjord)

on the on the 9th, and thereby forcing the norwegian goverment to evacuate north)

Even a few more beltboxes for the mashinegun platon on Fornebu, might have ashived the same result.

 

The same might have happend if the danes have held out (or denied the Luftwaffe the use of their airfields) for a day or two.

 

But after the first critical days, the germans had a clear upper hand.

More ships after those few days probably wouldn't change much as far as the outcome of the campain goes,

unless the allies could cling on to the northern half of the country.

 

The germans would still dominate the waters between Denmark and Norway,

so the german troops would continue to come in.

 

More ships in the Northsea prior to the 9th of april, might have led to

parts of the first german wave to be intercepted

and that might have changed the outcome completely.

 

If forinstance Gruppe II (Hipper and 4 destroyers heading to Trondheim with parts of the 138th mountain infantry regiment)

was intercepted prior to the 9th, the only germans tropps in the northern 2/3 of Norway,

would be i Narvik (and those troops was historicaly beaten by norwegian/brittish/french/polish troops)

and the allies could land directly in the Trondheim port.

 

More ships could obviously cause the germans even more losses of ships

(making the german fleet for Seelöwe even more inadequate)

 

 

 

With the "what if" don't forget there was a U-boot in a perfect firing position to sink warspite just before she devoured the bulk of the kriegsmarine's DD's but the captain panicked and withdrew so it works both ways.

Edited December 23, 2007 by Luke_Yaxley

[Olof Larsson]

With the "what if" don't forget there was a U-boot in a perfect firing position to sink warspite just before she devoured the bulk of the kriegsmarine's DD's but the captain panicked and withdrew so it works both ways.

 

AFAIK the issue was defective torpedoes,

with the magnetic pistols not working so far north,

causing premature detonations and so on.

 

I seem to recall several occations, when germans subs fired at brittish ships

during Weserübung, without any results.

 

As far as Narvik goes, during the first battle (the 10th) the german subs failed to detect the brittish destroyers.

 

The following night (10th to 11th) the german destroyers tried to break out of Narvik,

but encountered a few brittish destroyers and turned back to Narvik.

 

The night after that (11th to 12th) the U25 fired torpedoes at brittish destroyers,

but the torpedoes detonated prematurely.

 

The second battle of Narvik (the one with HMS Warspite) was the 12th,

but I can't seem to find any information about the german subs doing anything in the area that day

exept the U64 being anchored up and being destroyed by Warspites spotterplane.

[TonyE]

The invasion of Norway was an extremely risky operation.

It was based on the premesis, that the norwedians wouldn't resist

and there was no reserves avialable (the operation used the "left-overs" from "Fall Gelb".

 

In the first few days, very small differences could have turned the invasion to a failure.

 

A big "what if" would be if the government had listened to the chief of the generalstaff Colonel Rasmus Hatledal. On april 5th messages were received from the norwegian legation in Berlin that something was about to happen. Hatledal started a frantic work to persuade the government to mobilize, but was only taken into acount on the evening of april 8th, a few hours before the germans made their arrival.

[Marek Tucan]

If Sweden would join the allies, Bomber Command (and later USAAF) could operate from bases

with haft the distance (compared to brittish bases) to Berlin, increasing the bombloads that could be carried

and making fighter escort all the way to Berlin available earlier.

 

Furthermore many of the submarine shipyards and Peenemünde

would be far closer to allied airbases.

 

Not only that, U-boats would lose a safe (relatively) training zone, bringing the attrittion yet higher, and Germany would lose Swedish steel and ball bearings etc.

 

OTOH Allies might end up being fighting Stalin over Finland.

[Olof Larsson]

A big "what if" would be if the government had listened to the chief of the generalstaff Colonel Rasmus Hatledal. On april 5th messages were received from the norwegian legation in Berlin that something was about to happen. Hatledal started a frantic work to persuade the government to mobilize, but was only taken into acount on the evening of april 8th, a few hours before the germans made their arrival.

 

True. I seem to recall that the norwegians got information

from the swedish military attaché in Berlin as well.

 

But neither country reacted to the information in time.

 

Even the norwegian goverment having ordered a total mobilization at the 9th

(rather then a partial mobilisation by mail) would probably have changed the outcome.

Or the coastal artillery forts holding out for a few more hours.

 

It lesson to learn, when comparing the finns prior and during the winterwar

and the norwegians prior and during Weserübung, is how important it is

to be mentaly prepared (both for politicians, the generals and in service troops)

that a war might happend.

 

Not only that, U-boats would lose a safe (relatively) training zone, bringing the attrittion yet higher, and Germany would lose Swedish steel and ball bearings etc.

 

OTOH Allies might end up being fighting Stalin over Finland.

 

Well, the germans would still hold France and the bases there,

but manufacturing those subs would be harder

and the same for getting them to France.

 

The finnish issue is an interesting one.

The finns could obviously not seek help from the germans if the allies

holds Norway and if Norway and possibilly Sweden joins the allies.

 

But on the other hand the allies wasn't the best of friends with the USSR prior to Barbarossa,

with the brittons discussing to send troops to aid the finns

(via the iron-ore harbour of Narvik, the swedish iron-ore mines and parts of our steel industy)

and naval actions in the Black Sea, so hostileties between the allies and USSR shouldn't be excluded.

[Redbeard]

USA is unlikely to contribute with significant forces on land or in the air until 1941, but USA entering the war alreday in September 1939 is nevertheless going to make a huge difference. Germany will be pressed even more to defeat France ASAP. If that means attacking in say November 1939 (as plans had been made for) it probably means a German defeat. But even if France is run over like in our time line (OTL) it is unlikley to mean France quitting the war. In OTL the French considered it unlikely that UK would continue the war and therefore said "Yes please" to the relatively mild German conditions. If USA is already in the war the French options in continuing the war from overseas suddenly appear attactive.

 

France staying in the war will make a huge difference. First in the Mediterranean, which becomes an undisputed allied sea. Italy is ulikely to join the war on German side, as that obviously will mean Italy instantly loosing all her overseas possessions. Extra French pilots and planes will make BoB an even bigger allied victory. Norway is even more risky for Germany, but I think a failure will have mainly symbolic importance, as Germany got access to the iron ore she needed in northern France.

 

In the Far East the Japanese can't count on easy access to French IndoChina, which makes a surprise assault on Malaya/Singapore even more difficult that in OTL. Forces used in OTL to secure Vichy French possessions can now be used elsewhere.

 

The addition of the USN and the French Navy and Italy neutral will make the allied extremely strong at sea from the start - anywhere. The Japanese government is on a mission impossible.

In the Atlantic German U-Boats might still take a heavy toll on allied traffic, but hardly ever pose a serious threat.

 

Strategically the Balkans must offer some very tempting opportunities for the allies in this scenario, and Yugoslavia, Romania, Greece, Bulgaria and Turkey ought to be receptible to allied diplomacy. The biggest challenge will be not to get entangled before the required strength is available.

 

Seen from Germany it will be a very distressing situation to watch the allies and the Soviets grow stronger each day. Either they get rid of Hitler and conclude a peace ASAP, or they defeat one of the two big enemies before they grow too strong. USA/UK/France is obviously impossible right now, so it has to be SU - Barbarossa as historical - unless a major Balkan campaign is going on by mid 1941.

 

If Barbarossa it will be even more obvious, that anything but a total and quick victory is disastrous for Germany.

 

All in all the German chances are even more remote than in OTL. Their best chance probably being the allies getting seriosuly committed (and defeated) on the Balkans before the Germans are busy elsewhere. But OTOH with Italy and probably also Japan staying put the US/UK/French superiority will be so big that they probably can afford loosing a Balkan campaign - at least it will buy them some valuable experience.

 

Regards

 

Steffen Redbeard

[swerve]

France would find it very much easier to stay in the war if the USA was a co-belligerent. France bought US-made aircraft, guns & ammunition in 1939-40, to supplement its own production. There were therefore US factories producing weapons, parts & munitions which the French forces were using. The difficulty which the Commonwealth & Frances overseas territories would have had supporting French forces which fled the German conquest of Metropolitan France would no longer apply.

 

Therefore, even if we assume a successful Blitzkrieg in France, it is reasonable to assume a much greater effort by French forces to reach havens outside France: the entire fleet decamping to Oran loaded with everything & everyone they could carry, escorting every merchant ship & fishing boat that could carry soldiers, while the RN, the USN & the few French ships on the Atlantic coast evacuated what they could, & everything that could get into the air flew to England, Algeria or even Corsica. One can imagine the French & Americans becoming very close in this scenario, with the French providing the trained manpower the USA still lacked, & the USA the weapons the French no longer had the industry to build.

 

We therefore end up in 1940 with this possible scenario:

 

Germany occupying all of Denmark, Netherlands, Belgium & France (no Vichy!). Norway perhaps outside its grasp. But leave that for now.

 

The French government ensconced in Algiers, with several hundred thousand troops, the colonies to call on for manpower, safe behind the combination of its own fleet, the RN & the USN, being rapidly supplied with ammunition, spares, & fighters from the USA, & assured of future supplies.

 

Perhaps, Corsica in Allied hands.

 

Italy probably neutral, as Redbeard says, knowing that it would face a hostile Tunisia perilously close to Sicily, & instant loss of Libya, Ethiopia & the Dodecanese, if it joined the war.

 

No possibility whatsoever of Spain joining in.

 

What would Hitler do? Risk Barbarossa, leaving such strong enemies threatening to retake France as soon as they were ready?

Edited December 23, 2007 by swerve

[Olof Larsson]

What would Hitler do? Risk Barbarossa, leaving such strong enemies threatening to retake France as soon as they were ready?

 

Besides Barbarossa, he wouldn't have any offensive options,

except for going after still neutral nations in the Balkans.

 

So what would the states it the balkans and Turkey do?

 

With allied bases in either Greece, Turkey or even Crete, Ploesti is in harms way.

[swerve]

I just thought of something else. With Spain definitely out of the war, it might prove expedient for Portugal to openly join the fight from the start, thus giving the Allies use of the Portuguese Atlantic islands much earlier than in reality, & maybe air bases on the mainland of Portugal. Would make life pretty bloody hard for the U-boats. And maybe even more troops, if someone paid for decent kit for them.