Do US citizens born in Israel 1948 require a visa or Israeli passport to visit Israel?

If you are Jewish, you would be covered under the Israeli Law of Return, by which all Jews have an automatic right to visit or immigrate to Israel, a country whose official reason for existing is to provide a refuge for all Jews against the global scourge of anti-Semitism. If, however, you are not Jewish, then yes, you need a visa (but Israel does value tourism, and chances are you can get a visa).