Party hosts now face the threat of a civil lawsuit if they provide alcoholic beverages to people under the age of 21.

Gov. Arnold Schwarzenegger signed a bill into law Wednesday that would allow adults to be sued if they serve alcohol to people under the legal drinking age who are subsequently injured or killed as a result of the intoxication.

It is currently illegal for adults to provide alcohol to underage people, though previous law protected adults 21 and up from civil suit if they knowingly provided alcohol that resulted in the injury or death of a young person.

The bill, AB2486, was authored by Assemblyman Mike Feuer, D-Los Angeles. It received bipartisan support in the state Legislature.

"Governor Schwarzenegger was pleased to sign AB2486 because parents and adults have a responsibility to protect children and underage youth from alcohol," said the governor's deputy press secretary Matt Connelly in a written statement. "Adults that knowingly provide alcohol to a minor place both the minor and the larger community at risk. AB2486 enhances the seriousness of that offense and broadens the penalties against any parent or adult that knowingly provides alcohol to a minor."

Chris Norby, R-Fullerton, was the only Assembly member opposed to the bill, arguing that it unfairly shifts liability away from adults between ages 18 and 20, who should be "responsible for all their actions."