"No one should have to worry about getting a death threat because of the way he or she votes," said James Bopp Jr., an attorney representing two groups that supported Proposition 8, Protect Marriage.com and the National Organization for Marriage California. "This lawsuit will protect the right of all people to help support causes they agree with, without having to worry about harassment or threats."

The lawsuit, filed Wednesday in federal court in Sacramento, asks the court to order the secretary of state's office to remove all donations for the proposition from its Web site.

It also asks the court to relieve the two groups and "all similarly situated persons" from having to meet the state's campaign disclosure requirements. That would include having to file a final report on Proposition 8 contributions at the end of January, as well as reports for any future campaigns the groups undertake.

Proposition 8, approved by 52.3 percent of California voters on Nov. 4, reversed a state Supreme Court decision allowing gay marriage. The measure's opponents have asked the Supreme Court to overturn it.

The lawsuit filed Wednesday cites a series of incidents in which those who gave money to support Proposition 8 received threatening phone calls, e-mails and postcards. One woman claims she was told: "If I had a gun, I would have gunned you down along with each and every other supporter."

Another donor reported a broken window, one said a flier calling him a bigot was distributed around his hometown and others received envelopes containing suspicious white power, according to the lawsuit.