WASHINGTON - U.S. Supreme Court justices on Monday expressed skepticism toward part of an immigration law requiring the deportation of immigrants who commit violent felonies because of uncertainty over which crimes fit the bill and which do not.

The justices heard arguments in the government's appeal of a lower court's ruling that language in the Immigration and Nationality Act calling for deportation of legal immigrants convicted of a "crime of violence" was so vague that it violated their rights to due process of law under the U.S. Constitution.

The case involves a Filipino legal immigrant named James Garcia Dimaya who federal authorities ordered deported after he was convicted in two California home burglaries, though neither crime involved violence.

The ruling in the case could help clarify the crimes for which non-citizen immigrants may be expelled, affecting the Trump administration's policy of stepping up the removal of those with criminal records. There has been an intense focus on immigration issues since Republican President Donald Trump took office in January.

Conservative Justice Neil Gorsuch, a Trump appointee who joined the court in April, could cast the deciding vote.

Monday's arguments marked the second time the court has tried to tackle the case. It heard arguments in January when the nine-seat court was one justice short, but decided in June after Gorsuch brought the court to full strength to have the case re-argued.

Several justices questioned the role of courts in judging certain crimes as violent. "Lots of burglaries are done with open doors or with jimmying without injuring a lock," liberal Justice Sonia Sotomayor said.

Gorsuch told Trump administration lawyer Edwin Kneedler it was up to the U.S. Congress to clearly specify who is covered by laws it passes "when it's going to put people in prison and deprive them of liberty and result in deportation."

Kneedler said Congress had reasonably identified a category of crimes that carry the risk of violence, and suggested that the justices should defer to the immigration authorities.

Conservative Justice Samuel Alito appeared to back the government, suggesting that too loose a standard for finding non-criminal laws vague might cause many other laws to fall. "We might do a wonderful job of pruning the United States Code," he said, referring to the compilation of federal criminal and civil offenses.

Dimaya came to the United States from the Philippines as a legal permanent resident in 1992 at age 13. He lived with his family in the San Francisco Bay area, and had worked in several retail store jobs, including as a manager.

He was convicted in residential burglaries in 2007 and 2009 in crimes in which no violence was used and no one was injured. He was sentenced to two years in prison for each conviction.

In 2010, the government began a process to deport Dimaya. The Justice Department's Board of Immigration Appeals, the highest U.S. administrative body for interpreting and applying immigration laws, refused to cancel his expulsion because the law involved defined burglary as a "crime of violence."

In the federal criminal code, a "crime of violence" includes offenses in which force either was used or carried a "substantial risk" that it would be used.

The San Francisco-based 9th U.S. Circuit Court of Appeals ruled in 2015 that the definition as applied to non-citizen immigrants was unconstitutionally vague and can lead to arbitrary enforcement of the law.

The appeals court relied on a decision that same year by the U.S. Supreme Court, which found that a similar provision in a federal criminal sentencing law was overly broad.

The case was argued on the first day of the court's new term. A ruling is due by the end of June.