Immigrant who made a difference?

How about Albert Einstein? He fled Nazi Germany (he was Jewish), and was instrumental in FDR's decision to do the research to develop the nuclear bomb before the Germans could devise one.

I am no fan of his, but current Mayor of London, Boris Johnson, was born in New York. So I suppose he is an immigrant who became a "leader" (the second most powerful directly elected office in Europe after the president of France - Prime Ministers are appointed, not elected.)

Winston Churchill was the son of an American. Former PM Benjamin Disraeli, not an immigrant, but from a line of Italian Jews.

I sure can't think of any. Von Braun was a nazi.

But many made the ultimate sacrifice dying for this country.

Jennifer Granholm, governor of Michigan, is originally Canadian.

Winston Churchill's mom, Jenny Jerome, was American and he became an honorary one.

You could also go the "science and technology" route, such as Werner von Braun and Albert Einstein.

Cheech Marin

Any one of the founding father would work.