Einstein was born German, but he renounced his citizenship around the time the Nazis grabbed power IIRC. He was an American citizen when he died.
Edison...not enthusiastic about this one, keeping in mind how he screwed Tesla.
I don't really understand the anti-FDR sentiments. In retrospect, he did lots of things that damaged the American economy, but you can't really blame him- they didn't have the same understanding of economic principles that we do today, and he did it with the best intentions. And for better or worse, without him the office of the POTUS would't be the centre of power as it is today. I don't think he's the best, but he's certainly above the norm when it comes to American presidents. Dislike of him always seems to boil down to political convictions rather then his performance.
Reagan...also above the norm. "Reaganomics", wether you like it or not, did have the intended impact of reducing inflation and recession. However his record with managing his presedential duties in general is rather mediocre, the lowest point being the Iran-Contra scandal when he declared he had absolutely no knowledge about his staff's activity, wich doesn't speak well of him.
OTOH, I'm relieved nobody's mentioned JFK. Now there is a genuinely overrated president.
James Madison gets my vote. His support of divided government and institutionalized pluralism had decisive impact on the constitution, the greatest American statesman in the early years IMO.
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