What are the US citizen requirements for traveling out of the country?
What are the US citizen requirements for traveling out of the country? All travelers must have a passport book for international air travel. Please note that hospital-issued birth certificates, voter registration cards, and affidavits cannot be used. If you were not born in the United States, you can use your original Naturalization Certificate or Certificate of Citizenship.
What documents are needed to enter the United States and or to travel internationally?
A secure document is a passport, U.S. permanent resident card, or Stateless travel document, Re-Entry Permit, NEXUS card, U.S Merchant Mariner Card, military ID or emergency travel document issued by an embassy or consulate. U.S. passport cards are not valid for air travel outside the United States.
What is the penalty for U.S. citizens entering leaving the US on a foreign passport?
There are no penalties. The customs officials might be furious but the only thing they can do is confirm you're citizen and let you back in. As for leaving the US, the US doesn't have exit checkpoints so you can leave on any passport.