| Errorist76 said: To be honest and fair it's the Russians and Brits we have to thank the most! The Americans only joined the party when most of the fighting was over already and afterwards and until today try to steal the cake. |
There's a lot of truth in that. And it actually applies to WW1 as well: In both world wars, the US joined into the party late, when the main fighting armies had already suffered huge losses and had thus been significantly weakened.
Ultimately, that's a clever strategy: One is going to suffer hardly any own losses, yet get the full benefits of winning the war. And since the fighting takes place in "far, far away" as usual, there's no danger of your own country getting devastated. And, if you're as lucky as the US, you can even afterwards let Hollywood produce thousands of movies that will spread the illusion that your country played a much bigger role in the war than it actually did. 
WW1:
| Country | Killed soldiers | Total Soldiers | Percent |
|---|---|---|---|
| Germany | 2,00 | 13,25 | 15 % |
| Russia | 1,85 | 12,00 | 15 % |
| Austria-Hungary | 1,50 | 7,80 | 19 % |
| France | 1,30 | 8,10 | 16 % |
| British Empire | 0,85 | 7,00 | 12 % |
| Italy | 0,68 | 5,00 | 14 % |
| Osmanisches Reich | 0,60 | 3,00 | 20 % |
| Romania | 0,34 | 1,20 | 28 % |
| USA | 0,21 | 4,74 | 4 % |
| Serbia | 0,13 | 0,70 | 19 % |
| Bulgaria | 0,10 | 1,20 | 8 % |
WW2:
| Country | Killed soldiers | Killed civilians | Total casualties |
|---|---|---|---|
| Soviet union | 13.000.000 | 14.000.000 | 27.000.000 |
| Germany | 5.185.000 | 1.170.000 | 6.355.000 |
| China | 3.500.000 | 10.000.000 | 13.500.000 |
| Japan | 2.060.000 | 1.700.000 | 3.760.000 |
| Yugoslavia | 740.000 | 950.000 | 1.690.000 |
| USA | 407.316 | 407.316 | |
| Romania | 378.000 | 378.000 | |
| Hungary | 360.000 | 590.000 | 950.000 |
| Poland | 300.000 | 5.700.000 | 6.000.000 |
| Great Britain |
270.825 | 62.000 | 332.825 |
| Italy | 240.000 | 60.000 | 300.000 |
| France | 210.000 | 150.000 | 360.000 |
Btw, as the table above shows, even Britain and France had relatively small losses - the total number of fallen soldiers from Britain, France and the US combined adds up to just about 888.000 - which is just 20% more than the number of fallen soldiers from yugoslawia alone, and less than 7% of the number of fallen soldiers that the soviet union alone had to suffer. And the total number of casualties from those three countries combined is just about 1.1 million - less than 2/3 of the total number of casualties from yugoslavia alone, and just about 4% of the total number of casualties from the soviet union alone.
So, while we often think of Britain, France and the US when it comes to the question of who fought the Nazis, it's really the soviets who should get the vast majority of the credits. They did the hard and dirty work and suffered huge casualties, while Britain, France and the US only had hardly any casualties and became relevant when most of the dirty work had already been done and the Nazis had already been significantly weakened and were already on track to losing the war.
