The United States Senate Thursday finally passed its version of the immigration bill, which contains Western Hemisphere Travel Initiative-related amendments, including an extension of a key deadline, and an expansion of the types of documents citizens can use in lieu of passports.

As it currently stands, beginning December 31, 2006, travelers to and from the Caribbean, Bermuda, Panama, Mexico, and Canada—via sea or air—must have a passport, or other accepted document, to enter, or re-enter the United States. After December 31, 2007, that requirement extends to all land border crossings as well.

The Senate earlier had attached an amendment to the immigration bill, offered by Sens. Patrick Leahy, D-Vt., and Ted Stevens, R-Alaska, extending that latter deadline 17 months. On Thursday, the Senate also attached an amendment, offered by Sen. Norm Coleman, R-Minn., which expands the kinds of documents acceptable for travel (such as an affordable passport card) and requires a pilot program to test new documents and technologies before the deadline can be implemented.

The Senate and the House of Representatives must still reconcile their competing versions of the immigration bill before it goes to President George W. Bush.