Keyse Jama, from Somalia, urged the court to stop the government from sending immigrants back to countries that have not agreed to take them back. Jama was convicted of assault in Minnesota, and a judge ordered his deportation because of the crime.

Jama's lawyer told justices that deportation would endanger his client and be impractical. John Lunseth of Minneapolis said the plan was to put Jama on a flight into Somalia where "he would become a stateless person with no travel documents or identity papers in a war-torn region with no central government."

A divided appeals court panel ruled with the Bush administration last year, saying that because Somalia has no government it would be impossible to get official approval for Jama's return. Jama came to the United States in 1996 as a refuge and was arrested after getting in a fight with another Somalia man three years later. The case is Jama v. Immigration and Naturalization Service, 03-674.

In the other case, Leocal v. United States attorney general, 03-583,

The question is whether a DUI accident that causes injury is a "crime of violence," that allows the government to starts deportation proceedings. Justices will hear an appeal from a native of Haiti who was convicted in an accident in 2000 in the Miami area. Josue Leocal, 47, was sentenced to more than two years in prison on the felony charge. His lawyer argued that he had never been arrested before during his nearly 20 years in the United States and has now been treated for substance abuse.