The United States’ Western Hemisphere Travel Initiative (WHTI), which heightens the document requirements for entering and re-entering the United States by land or sea, went into effect on June 1. The WHTI requires all citizens of the US, Canada, Mexico, Bermuda, and Caribbean nations to have a passport or other form of approved documentation in order to enter or depart the US. As reported by JURIST, some have voiced concerns about the rules’ impact on tourism in the US and Canada, whose border has been called the "world's longest undefended border." The WHTI rules were promulgated under the Intelligence Reform and Terrorism Prevention Act of 2004, which required the Department of Homeland Security and the Department of State to develop and implement a plan requiring travelers to present secure identification documents when entering or re-entering the United States.