Alaskans will lose their right to smoke a joint in the privacy of their homes Sunday, but the state's ban on marijuana promises to end up in court before the smoke clears.

On Monday, opponents plan to file a civil lawsuit in state Superior Court challenging the constitutionality of the new law, which voters passed in November.For nearly 16 years, Alaska has had the nation's most liberal marijuana law, one that gave adults the right to possess in their homes less than 4 ounces.

That law resulted from a 1975 state Supreme Court decision, which said the health threat posed by marijuana was insufficient to warrant government intrusion on Alaskans' privacy.

On Sunday, possession of small amounts of pot will become a misdemeanor punishable by up to 90 days in jail and a $1,000 fine.

"Constitutionally, the law's dead on arrival," said Jamie Bollenbach, executive director of the Alaska Civil Liberties Union. "There's no reason to believe it won't be overturned again."

Alaska is one of only a few states that provide a specific right to privacy in their constitutions. Besides privacy, opponents will argue that a law passed by voters cannot overturn a decision of the state's highest court, said Bob Wagstaff, an Anchorage lawyer who successfully argued the 1975 marijuana case.