Why did the allied powers join world war II?

Question: Why did the allied powers join world war II!?

i need to know why the countries that made up the allied powers joined the war!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

Why!? Because they didn′t want Hitler to march freely into their capitals!.
Hitler wanted "lebensraum" (living space) for Germany and was prepared to crush anyone that got in his way of getting it!.Www@QuestionHome@Com

Well several of them were being attack by Germany (France, Britain)!. And then the US joined for obvious reasons, they were attacked by the Japanese in Pearl Harbor!.Www@QuestionHome@Com

Allied Side: USA, Great Britain, Free French, Poland, Canada, China, Soviet Union, Brittish Colonies, India, Australia, Belgium, Sweden, Finland, Italy after american capture!.

Axis: Germany, Libya, Algiers, Italy, Greece, Japan, Soviet Union until operation BarbarossaWww@QuestionHome@Com

There would have been no war without them!.Www@QuestionHome@Com

Is that how your history teacher posed the question!? It's misleading and quite strange!. I mean most of the "allied powers" were attacked by Germany or its allies!. So it wasn't exactly "joining" the war as it was being thrown head first into it!. I guess you could say England was the only one that didn't face a direct attack before it "joined" the war, because, unless I am mistaken, it sent troops into France to defend its ally against attack!. But, England knew that if France fell, they were next in line!.Www@QuestionHome@Com

The U!.S!. joined on December 7, 1941 with the bombing of Pearl Harbor near Hawaii!.Www@QuestionHome@Com