How can i leave the US without a passport?

Answer 1

If you want to enter a foreign country you do. The passport isn't for leaving the country of citizenship. Its for entry into foreign countries. Even some cruise lines require a passport. To get back into the country you also need one. All American citizens now need a passport.

Answer 2

You don't need a passport to leave-- you need the passport to get back in. Foreign countries are likely to require a passport in place of a visa.