WI: The USA joins WWII in September 1939

I know it's probably a bit ASB, as it would require an early PoD and big political changes, but I've had this thought, and I'm curious:

How would WWII have been affected if the United States joined Britain and France in declaring war in September 1939? For example, if they too had guaranteed the independence of Poland in a similar or identical declaration to that of the original Allies. And history somewhat repeats itself - the US joining their old ally France against a belligerent Germany. Again.

Obviously, I'm not proposing any changes in their military strength or readiness at this point, just their politics, so I'm assuming that their contribution for a year or two will be mostly in terms of production and supplies until their forces can really get going. Further out, I imagine US involvement in the European war will also affect Japanese policy one way or another.

What do people think?
 
Your POD would probably have to be much further back, say Wilson handles things better in the US after Versailles and gets the Senate to ratify membership of the League of Nations.
 
Like you said it is hard to see happening but I suppose Hitler could really lose his cool about something and declare war himself as the guy was bonkers. If it did happen it helps quite a bit. While the US is gearing up for war it plays quartermaster. The first thing that comes is food and ammo as it has plenty of the first and you can ramp up ammo production faster than you can tanks or planes. France may well not fall, not due to US troops which might just start to trickle in but due to shipments of anti-aircraft and anti-tank guns along with their ammo. Even some fighter aircraft might start trickling in. Even Brewster Buffaloes were viable in 1939. By mid to late 1940 you start getting troops to trickle in.
 
Your POD would probably have to be much further back, say Wilson handles things better in the US after Versailles and gets the Senate to ratify membership of the League of Nations.

Specifically, Wilson would have to agree to the so-called Lodge exemption which specified certain circumstances in which League action would be non-binding on the U.S. If he had done so, League of Nations membership would likely have sailed through the Senate.
 
I know it's probably a bit ASB, as it would require an early PoD and big political changes, but I've had this thought, and I'm curious:

How would WWII have been affected if the United States joined Britain and France in declaring war in September 1939? For example, if they too had guaranteed the independence of Poland in a similar or identical declaration to that of the original Allies. And history somewhat repeats itself - the US joining their old ally France against a belligerent Germany. Again.

What with? In 1939 the US Army was tiny, with few if any modern weapons. The US Navy was ill equiped to act as convoy escorts. US Army Air Corps aircraft were at best marginal for combat in Europe and again too few in number. Like the French tanks were tied to the infantry in penny packets, and those tanks they had would have been easy prey for the Panzers.
 
What with? In 1939 the US Army was tiny, with few if any modern weapons. The US Navy was ill equiped to act as convoy escorts. US Army Air Corps aircraft were at best marginal for combat in Europe and again too few in number. Like the French tanks were tied to the infantry in penny packets, and those tanks they had would have been easy prey for the Panzers.


It could and would play quartermaster while its gearing up. That is what the US did OTL only later.
 
What with? In 1939 the US Army was tiny, with few if any modern weapons. The US Navy was ill equiped to act as convoy escorts. US Army Air Corps aircraft were at best marginal for combat in Europe and again too few in number. Like the French tanks were tied to the infantry in penny packets, and those tanks they had would have been easy prey for the Panzers.

Yes but just because they weren't prepared doesn't mean they couldn't be draw in. IF the USA were a member of the LON and backed the British and French against German expansionism in the 30's perhaps Hitler is sufficiently enraged that when Britain and France declare war over Poland(and Poland is bound to happen if Hitler is in power), he decides to declare war on the USA. That's not to mention he may be afraid of the US supplying his enemies with war materials, so since the USA isn't as you say a military threat, why not choke off that pipeline?

Sure in the long term its suicidal but so was Hitler declaring war on the USA when he did OTL.
 
I could see Hitler easily provoking the United States, say, within a few months after the war began. He would probably still win in France (the U.S. would not be able to give much help in the battle of France, not yet being properly mobilized) but the U.S. being in the game might mean the following (among other things):

1. U.S. sending aid to France and the French not giving up but fighting on from North Africa, knowing that the most powerful industrial nation in the world is on their side.

2. Britain not so worried about invasion, and the U.S. getting some planes over to help with the BOB plus at least a division of troops with artillery (if the Canadians could do it, the U.S. could).

3. U.S. occupies Iceland first, so Brits don't have to divert troops for that.

4. U.S. leans on the Irish for bases for the submarine war. Promises that these will be U.S., not British, bases.

5. U.S. in the game means the Brits don't have to worry about Franco (or the Turks).

6. U.S. forces sent to Britain early on means the Brits can confidently send more troops and planes and ships to the Med. Working with the French in Algeria, they quickly drive the Italians out of North Africa and thoroughly decimate the Italian navy much earlier. Invasion of Sicily in 1942. (This assumes Mussolini doesn't remain neutral; with the U.S. in the war he very well might.)

7. U.S. will restrain Churchill from sending troops to Greece in 1941 (although with Musso remaining neutral in the larger war this might become a moot point).

8. Earlier success against the Germans on the oceans, both in driving away their surface warships and in dealing with their submarines. The U.S. had one of the biggest navies on earth, and although they lacked experience running convoys Admiral King will not be distracted by the Pacific and will begin attending to the U-boat problem without delay. Also, the Germans simply didn't have that many U-boats at the beginning of the war.

9. U.S. is joining the war over two years earlier, but it is starting from a much lower level of mobilization than 1941 in OTL. So they won't be up to something equivalent to Torch until late 1941. Expect D-Day in 1943. And expect it to be more difficult than our D-Day, because the Soviets will not yet have bloodied the Germans quite as much.

10. Portugal gives the Allies the use of the Azores a year earlier.

11. No war with Japan. The U.S. will be too highly mobilized by late 1941 and the French and British will be much stronger in the Far East than in TTL. (Also, good advanced radar in Hawaii.)

12. The Soviets will end up with much less of Eastern Europe at the end of the war.

13. U.S. casualties on the Western Front will be double what they were in TTL, but since there will be no Pacific war this will be sustainable with the public.

14. Ike will still be the Allied commander--Marshall didn't have anyone else with the personality and the understanding of strategy to do the job properly. With no Battle of El-Alamain, Ike doesn't have to deal with Monty. Harold Alexander becomes the commander of British and Canadian forces in the Battle of Normany and thereafter, and Antwerp gets taken and those island cleared a lot earlier.

15. The war from D-Day to the German surrender will take about 18 months rather than 11 months.
 
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I could see Hitler easily provoking the United States, say, within a few months after the war began. He would probably still win in France (the U.S. would not be able to give much help in the battle of France, not yet being properly mobilized) but the U.S. being in the game might mean the following (among other things):

1. U.S. sending aid to France and the French not giving up but fighting on from North Africa, knowing that the most powerful industrial nation in the world is on their side.

2. Britain not so worried about invasion, and the U.S. getting some planes over to help with the BOB plus at least a division of troops with artillery (if the Canadians could do it, the U.S. could).

3. U.S. occupies Iceland first, so Brits don't have to divert troops for that.

4. U.S. leans on the Irish for bases for the submarine war. Promises that these will be U.S., not British, bases.

5. U.S. in the game means the Brits don't have to worry about Franco (or the Turks).

6. U.S. forces sent to Britain early on means the Brits can confidently send more troops and planes and ships to the Med. Working with the French in Algeria, they quickly drive the Italians out of North Africa and thoroughly decimate the Italian navy much earlier. Invasion of Sicily in 1942. (This assumes Mussolini doesn't remain neutral; with the U.S. in the war he very well might.)

7. U.S. will restrain Churchill from sending troops to Greece in 1941 (although with Musso remaining neutral in the larger war this might become a moot point).

8. Earlier success against the Germans on the oceans, both in driving away their surface warships and in dealing with their submarines. The U.S. had one of the biggest navies on earth, and although they lacked experience running convoys Admiral King will not be distracted by the Pacific and will begin attending to the U-boat problem without delay. Also, the Germany simply didn't have that many U-boats at the beginning of the war.

9. U.S. is joining the war over two years earlier, but it is starting from a much lower level of mobilization than 1941 in OTL. So they won't be up to something equivalent to Torch until late 1941. Expect D-Day in 1943. And expect it to be more difficult than our D-Day, because the Soviets will not yet have bloodied the Germans quite as much.

10. Portugal gives the Allies the use of the Azores a year earlier.

11. No war with Japan. The U.S. will be too highly mobilized by late 1941 and the French and British will be much stronger in the Far East than in TTL. (Also, good advanced radar in Hawaii.)

12. The Soviets will end up with much less of Eastern Europe at the end of the war.

13. U.S. casualties on the Western Front will be double what they were in TTL, but since there will be no Pacific war this will be sustainable with the public.

14. Ike will still be the Allied commander--Marshall didn't have anyone else with the personality and the understanding of strategy to do the job properly. With no Battle of El-Alamain, Ike doesn't have to deal with Monty. Harold Alexander becomes the commander of British and Canadian forces in the Battle of Normany and thereafter, and Antwerp gets taken and those island cleared a lot earlier.

15. The war from D-Day to the German surrender will take about 18 months rather than 11 months.


The US couldn't send France troops but it could send them food (which frees up famers that France can turn into infantry), lots of ammo which means France could really be lavish with firepower and probably some old weapons which France could use and would be better than nothing. At the very least France should hold out longer. Also the Brits would probably send more squadrons of fighters down to France knowing the US will simply replace them.
 
What with? In 1939 the US Army was tiny, with few if any modern weapons. The US Navy was ill equiped to act as convoy escorts. US Army Air Corps aircraft were at best marginal for combat in Europe and again too few in number. Like the French tanks were tied to the infantry in penny packets, and those tanks they had would have been easy prey for the Panzers.

This is what I agree with. The US did not have the political or popular will to offer up blood and gold to "guarantee freedom" to Czechoslavakia or Poland, and did not possess the military might to fulfill such an obligation. The 1940 USAAC complement of combat aircraft was smaller than Britain's RAF, with frontline A/C being P-36s and B-18s, neither considered combat-capable.
 

Hkelukka

Banned
Germany and SU as the ideological enemies of US-UK-Fra due to WW1 sign a common alliance.

SU goes south towards India-Pakistan-Turkey-Iran, a joint attack on Poland- Baltics- Balkans and Germany attacks France-Lowcountries-UK long before the US can join in on any way.

Followed by a 1940 war with Germans dying in low-countries france and SU troops dying in India.

Ger-SU probably collapses sometime in the 1942 or so.

Assuming no German-SU alliance, General coup in Germany either during or just after Poland. followed by a Hitler getting a bullet to the brain and Germany re-negotiating the Polish borderlands and disarming under US-UK-French oversight.

War is seen as a "general resentment at the unfair treatment of both the Soviet union and the Germans that was quickly solved with minimal bloodshed and the post-war peace will be much more just to all sides"

"let no austrian corpral missing his German momma start another war"
 

iddt3

Donor
It seems likely that a more involved US would also be more militarily up to spec, OTL the only real threat was the Japanese and we kept up a world leading navy to deal with that.
 
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