Here in the U.S., a citizen faces no restrictions at all if they want to leave the country - they're free to go anywhere that they can get into. It's not Columbia's job to prevent people from leaving.

I think there may be some restrictions on travel. For example:

Linus Pauling, a Nobel Prize-winning chemist, faced restrictions on travel due to the Internal Security Act of 1950, which broadened the government's power to limit the travel of political dissidents1. Despite these restrictions, he was eventually granted a passport to travel to Sweden and receive the Nobel Prize in Chemistry2.

I think the law states that a US citizen has to depart and arrive in the US with a valid US passport. I think the US government can withhold the issue of a passport.

Also, the Court has rules that due process is required prior to restricting travel.

However, as a practical matter, there is no passport control when leaving the country, so if a person has citizenship in another country they can leave and the government would not know. However, if no dual citizenship, then the airline will not allow you on the plane.

Aussi