[Albion Wilde]

When the Soviet union imploded and Israel took in 2 million Russians, they had to teach them how to be Jewish. That’s only after 80 years.

Well, Nehemiah and Ezra had to do the same thing after the approximately 66-year Babylonian exile, when the Israelites returned to Jerusalem. Thusly, Judaism survived.

Of course, in Biblical times the ruling power could do things we can't do today. After reading the law of Moses to the Israelites, Ezra reminded them that the Torah forbid intermarriage and made them divorce their pagan spouses and either Judaize the children or give them up.

[Mr. Blond]

Israelites weren’t exiled to Babylon, the Judeans were. Who returned from Babylon is a matter of debate.