RAM, that was not answered because I was going home. Anyway, you do not need to be so rude, IMO. We try to show our superiority to Americans, right? j/k

And, while we are at it, some facts:
Spain, 1.936, Republican Democratic Government allowed church burning, and political prosecution.
Spain, 1.936, crime raging, economic crises, local governments chaos.
Spain, 1.936, anarchists and communists pushig for power, but by means of wild & violent labour strikes, instead of democratic vote.
Spain, Civil War, Republican Democratic Government is overan by anarchists and communists supported by the PCUS (U.S.S.R. communist party). The anarchist are massacred by the communists in Barcelona shortly after. Communists became, in fact, the leading force of the Republican side.
I am not saying fascists in Spain were right (btw, technically speaking, Franco was not a fascist but a dictator) and I am not making an apology fo the Coup d'Etat, nor the Civil War, Heaven forbid. I am only saying that nothing, and especially Spain in the thirties, is white or black.
On the dictatorship support, bear in mind that U.S.A and U.S.S.R. were in fact fighting WWIII (cold war). In a hot war, civil casualties die under the bombs, I guess in a cold one, under the different tyranies supported by each side. Both sides of the conflict were ugly monsters those days, and we were caught in the middle. As a personal choice, I rather like the U.S.A. ugly face than the U.S.S.R. one, and not only by economic standards.
Now, on an answer to Miko, Hitler's target was, as the Deutsch national himn says, "Deutschland über alles", a superior nation with a superior race. With this philosopy in mind, clash with the U.S.A. was only a matter of time. Should not the U.S.A. get involved in European War, the consequences would be much, much worse for you at the end. Hitler would have the time to consolidate his conquers, and climb a step higher on the ladder when he felt his feet on solid ground. In fact, FDR saw it very clearly, and IIRC, he was one of the strongest voices against isolatinists. Wise man, thank god.
European continental nations lacked what Spanish Civil war meant: a general essay on WWII, on the axis side. And they lost the only chance they had, for a brief moment to attack Germany just after the Sudeten anexion, when they were still weak. But having France & U.K. agreeing on the when, what and how on that times is utopic. Heh, even now it's utopic

So to the why the U.S.A. got involved into WWII, it is because your president saw clearly that isolationism was not the answer, but it was the snake egg. The Lend & Lease Act (I think it is the right name) is only an intermediate step towards full involvement.
For what plan Marshall is concerned, It's really brilliant. But take into account that besides the evident help it provided to rebuild Europe, it is also a wonderful business for the U.S.A. (and I am not critisizing it. I believe Marshall plan was the most effective weapon against rampant Soviet influence), and boosted U.S.A. exports big time.
On a side note, I think If we go on talking on this subject, we should move the thread to the History forum.
Cheers,
Pepe