From The Los Angeles Times
Here's the paradox. The U.S. immigration system severely limited the number of German Jews admitted during the Nazi years to about 26,000 annually — but even that quota was less than 25% filled during most of the Hitler era, because the Roosevelt administration piled on so many extra requirements for would-be immigrants. For example, starting in 1941, merely leaving behind a close relative in Europe would be enough to disqualify an applicant — on the absurd assumption that the Nazis could threaten the relative and thereby force the immigrant into spying for Hitler.
Why did the administration actively seek to discourage and disqualify Jewish refugees from coming to the United States? Why didn't the president quietly tell his State Department (which administered the immigration system) to fill the quotas for Germany and Axis-occupied countries to the legal limit? That alone could have saved 190,000 lives. It would not have required a fight with Congress or the anti-immigration forces; it would have involved minimal political risk to the president.

World War II is often mythologized as the war to stop the Holocaust, but it's forgotten that there was a non-violent way we could have saved many Jews--if we had just liberalized our immigration policies