FDR and the unions turned back refuge ships from Germany wanting to embark in the US. The refugees of course died when the got back. FDR in our family is anathema.
Granted my history is thin for this era, but as I currently understand it, Eastern European Jews began heavily immigrating to the U.S. in the 1880s. This wave of Jewish immigration was responsible for bring socialism to the U.S. and making it flourish in the unions. American natives got tired of it and pressured Congress to pass the Emergency Immigration Act of 1921 which heavily restricted new immigrants.
The SS St. Louis sailed from Germany in May 1939 carrying 936 (mainly German) Jewish refugees. On 4 June 1939, it was also refused permission to unload on orders of President Roosevelt as the ship waited in the Caribbean Sea between Florida and Cuba. Initially, Roosevelt showed limited willingness to take in some of those on board. But the Immigration Act of 1921 made that illegal and public opinion was strongly opposed. The ship returned to Europe. 620 of the passengers were eventually accepted in continental Europe, of these only 365 survived the Holocaust.
The Immigration and Nationality Act of 1965 (Hart-Celler Act, INS, Act of 1965, Pub.L. 89–236) abolished the National Origins Formula that had been in place in the U.S. since the Emergency Quota Act of 1921. It was proposed by U.S. Representative Emanuel Celler (D-NY). His paternal grandparents and maternal grandmother were German Jews. This was the culminating moment in Celler's 41-year fight to overcome restriction on immigration to the U.S. based on national origin.
The Hart-Celler Act replaced the EQA with a preference system that focused on immigrants' skills and family relationships with citizens or U.S. residents. It marked a radical break from the immigration policies of the past. The law as it stood then excluded Asians and Africans and preferred northern and western Europeans over southern and eastern ones. At the height of the civil rights movement of the 1960s the law was seen as an embarrassment by, among others, POTUS #35 JFK, who called the then-quota-system "nearly intolerable". Some historians thought that JFK saw a chance for retaliation in response to the anti-Irish Catholic bigotry by WASPs he encountered as a younger man. After Kennedy's assassination, POTUS #36 LBJ signed the bill at the foot of the Statue of Liberty as a symbolic gesture. In order to convince the American populace - the majority of who were opposed to the act - of the legislation's merits, its liberal proponents assured that passage would not influence America's culture significantly. POTUS #36 LBJ called the bill "not revolutionary", SoS Dean Rusk estimated only a few thousand Indian immigrants over the next 5 years, and other politicians, including Senator Ted Kennedy, hastened to reassure the populace that the demographic mix would not be affected; these assertions would later prove wildly inaccurate.