Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. AP Explains: Questions and Answers on New US Asylum Ban Associated Press SAN DIEGO - A major immigration policy shift took effect Tuesday to deny asylum to anyone who shows up on the Mexican border after traveling through another country. The dramatic move will likely have the biggest impact on Guatemalans and Hondurans, who must pass through Mexico to reach the U.S. by land. Together, they account for most Border Patrol arrests, and they tend to travel in families. The change drew an immediate lawsuit from the American Civil Liberties Union and the Southern Poverty Law Center in federal court in San Francisco. Here are some answers to questions about the policy, how Europe has confronted similar challenges, and how Mexico and Central American nations have responded. How does the new policy work? Asylum-seekers must pass an initial screening called a "credible fear" interview, a hurdle that a vast majority clear. Under the new policy, they would fail the test unless they sought asylum in at least one transit country and were denied. They would be placed in fast-track deportation proceedings and flown to their home countries at U.S. expense. .