Maybe not even the most attractive one.

Remember, thousands of those now-Israeli Jews have "made aliyah" from all over the planet. Many of those did so not out of duress (economic or otherwise), but out of a calling they felt to live in Eretz Yisroel. A lot of them started life as Americans. Others are first- or second-generation descendants of that sort of immigrants. To many of them, "the old country" is in the Western Hemisphere.

A drop from the potential bucket, assuredly... but there are thriving Jewish communities in Latin America, Canada, Australia, South Africa, etc., capable of persuading their governments to open up.

Given your disastrous scenario, I wonder how many ports would be closed to the refugees, as America was closed to many trying to escape Hitler's Final Solution.