It would help if you could also include events from the 1920s and 1930s that predate the beginning of WWII and events that occured befored the U.S. entered war to answer the question.
Assuming that I would be the same person as I am today, my politics would have definitely leaned towards internationalism because appeasement and pseudo promises from an insane dictator are no basis for foreign policy strategies. By July 1941 Hitler had swept across Europe, nations fell like domino's with the exception of Britain. Although we now know that the Nazis were spying close to U.S. shorelines, I think anyone who followed international affairs could have figured out Hitler was not about to stop in England. Granted it might not have happened right away but he clearly believed that he could propagate a new race and rule the world. The man and his ideological agenda had to stopped....
These questions are always difficult to gauge and answer effectively, because if I had lived through the Depression and into the early 1940s, my life experiences and my outlook on politics, the world and life in general would likely be much different than mine are now. That being said, I completely understand this is just a question for a class you need to address.
So with that grain of salt, I believe I would have been isolationist. With the war in Europe turning ugly and massive by July of 1941, I believe I would have had little desire to involve my country. We just got back on our feet, I would have been gainfully employed for perhaps the first time in a long while and we had already bailed Europe out once before. I probably would have argued this was "Europe's War" and that we should stay out of it, especially given the Nye Committee's findings (see link below)
Also by July of 1941, war between the Soviet Union and Germany had begun, and the Soviets, while caught badly by surprise, outnumbered the Germans, had a vast country and vast resources, and I probably would have figured that they could handle the Germans on their own, and that the danger to Britain was lessened because of it.
The Great Depression of the 1930s preoccupied us and isolated us. The social dislocation was so great during that time, that you could find few, even by the early 1940s, who thought getting into World War II was a good idea. Pearl Harbor was what finally united Americans behind the war, although the Cash and Carry policy, Lend Lease Act and the Destroyer Deal all brought us closer to war before that happened, as did the sinking of some American ships pulling convoy duty to Britain.
Just to present a different opinion...
I think hindsight could actually push me to feel more isolationist than internationalist. All of what the previous posts have said is true, and sitting back and watching Hitler do what he did would be sickening.
At the same time, watching what we did in WWII is also sickening, we bombed civilian populations, dropped nuclear bombs to send a message to Stalin knowing the people we dropped them on were in the process of surrendering, sent thousands and thousands of young men to their deaths and thousands of others to be maimed physically and mentally. We didn't prevent the holocaust, we didn't prevent Stalin from killing somewhere in the range of thirty million people in Russia, etc., we probably provided some of the weapons he used to do it.
So I would say that I would be a strong defense-minded isolationist. We could certainly have protected ourselves from Hitler, and he wouldn't have lasted very long anyway given the number of plots against him and his deepening insanity. (hopefully)
It is very easy to answer this question with hindsight. I mean, I wonder the reasonability of anyone who would say that knowing what is known about the time period that isolationism was a good plan of action. That being said, if I, as I am now, were living back then, I would have probably been very mindful of the fact that many were saying that something is horribly wrong in Germany and with the Nazis. The specific violations against Jewish people on human, political, and economic rights levels would have been enough for me to say that Hitler needs to be stopped. At the same time, the annexation of nation after nation would be justification to me that Hitler's promises of being appeased were not working. At the same time, I would have been persuaded by the idea that European world leaders were falling by the wayside in their attempts to stop Hitler and this would be reason enough to become involved. Yet, all of this is really easy to call now that we know what is meant to be known. I think that this particular period of history is one of the most interesting precisely because something that is so evident and lucid to us now in retrospect was so murky and unclear back then.
As of July of 1941, I think I would have been an internationalist. A couple of years before, I might have been isolationist. The reason for the change would be the extent to which Hitler had proven that he was aggressive. By July 1941, I would have thought that Hitler was just too big of a danger.
By July of 1941, Hitler had essentially conquered all of Europe except for Great Britain. And it looked as if he would conquer the Soviet Union as well. Because of that, I would have been worried that he and the Nazis would completely dominate Europe and even Asia (with the help of Japan, which was taking things like Vietnam). I would have worried that he would have turned his attention to the Americas.
So I would have looked at the fact that Hitler was being so aggressive and I would have worried that if we did not get invovled in Europe that it would be too late and all of Europe would be dominated by the Nazis. I would worry that Europe and Asia combined would be too much for the US to overcome if Hitler and the Japanese turned their attention to us.
I would have been isolationsit up until July, after the attack on the States, I would have been screaming for blood. While it wouldn't have been such a big deal if we were taking part in the war, the States were at this time a neutral country for the most part. There was no reason for a pre-emtive strike, it was in doing this the the Axis sealed their fate.