The US needs to send a phib to bring out the Americans (charge airfare to the tourists) and then offer evac services to citizens of friendly countries - there arent many, but there are a few.
I dont know what a Phib is but Im thinking we deploy the 101st or 75th Rangers, take charge of the airport and evacuate all Americans. Then, let the Haitians have their way with each other.
Landing ships the size of a French aircraft carrier. 1600 marines, attack aircraft, helicopters, and Ospreys. https://en.wikipedia.org/wiki/America-class_amphibious_assault_ship
Or lthe slightly smaller Tarawa class, with 1700 Marines, anwhere from 4 large landing craft to 44 small ones, helicopters and fighters. https://en.wikipedia.org/wiki/Tarawa-class_amphibious_assault_ship