By James Vicini
WASHINGTON (Reuters) - The Supreme Court upheld a federal law on Monday that allows the U.S. government to keep sex offenders in custody for an indefinite time beyond their prison sentences.
By a 7-2 vote, the high court ruled that Congress did not exceed its power when it enacted the 2006 law providing for the continued detention of sexually dangerous federal inmates who have completed their prison terms.
The ruling was a victory for Solicitor General Elena Kagan, who had argued the case. She was nominated by President Barack Obama last week for the Supreme Court vacancy created by the retirement of Justice John Paul Stevens.
The Supreme Court in 1997 ruled that U.S. states could confine dangerous sex offenders to mental institutions after they served their sentences. The Obama administration argued the federal government also has the same authority.
Politicians from both political parties have backed tougher measures to deal with sex offenders in the U.S. criminal justice system to try to make sure they do not commit repeat crimes.
Crime has been a major issue in U.S. politics and many elected officials are sensitive to any accusations from opponents that they are too lenient on violent convicts. There has been ongoing public concern over repeat sexual offenders.
A U.S. appeals court struck down the law for exceeding the limits of congressional authority and for intruding on police powers the U.S. Constitution reserves for the states, many of which have their own similar laws.
The Supreme Court overturned that ruling in a majority opinion written by Justice Stephen Breyer.
Breyer said the high court only ruled on whether Congress had the power to adopt the law, not on whether the law violated any rights guaranteed by the Constitution.
The law had been challenged by five inmates who had been kept in custody at a federal prison hospital in North Carolina after their sentences ended.
The federal law defined sexually dangerous as someone who suffered from a serious mental illness, abnormality or disorder and would have difficulty in refraining from sexually violent conduct or child molestation if released.
About 100 federal inmates have been identified for detention after serving their sentences.
Before 2006, the federal government's civil commitment power only covered those in U.S. custody who have been declared incompetent to stand trial, found not guilty by reason of insanity or determined after conviction to be mentally ill.
The law at issue also established a national sex offender registry, increased punishments for some federal crimes against children and strengthened child pornography protections. Those provisions were unaffected by the ruling.
The Supreme Court case is United States v. Comstock, No. 08-1224.
(Editing by David Alexander and Doina Chiacu)