U.S. Citizens can apply for a passport card that allows re-entry into the U.S. at border crossings or sea ports  from Canada, Mexico, countries in the the Caribbean region (which includes 17 nations), and Bermuda.
The 17 Caribbean nations are: Anguilla, Antigua and Barbuda, Aruba, Bahamas, Bermuda, British Virgin Islands, Cayman Islands, Dominica, Dominican Republic, Grenada, [...]