"The U.S. Department of State and U.S. Department of Homeland Security (DHS) have announced that citizens of the United States, Canada, Mexico, and Bermuda will now be required to present a passport to enter the United States when arriving by air from any part of the Western Hemisphere. This requirement will take effect in January 2007. The new travel document requirements are part of the Departments' Western Hemisphere Travel Initiative (WHTI), which will be implemented in two phases. The first phase involves travel by air. On January 1, 2008, the requirement will include all air, sea, and land-border crossings."