The campaign to legalize and tax marijuana in Washington state has received another surprising endorsement.

Republican U.S. Senate hopeful Michael Baumgartner tells The Associated Press he believes it's a good step toward changing what he calls the wasteful government policy of prohibition.

Baumgartner is challenging Democratic Sen. Maria Cantwell, who has not taken a position on the measure. Initiative 502 would legalize possession of up to an ounce of marijuana by people over 21 and allow them to buy it at state-licensed stores.

Budget officials say it could bring Washington hundreds of millions of dollars a year in taxes, though pot would remain illegal under federal law and it's unclear whether the Justice Department might sue the state.

Other I-502 supporters include former Seattle FBI head Charles Mandigo, former U.S. Attorneys John McKay and Kate Pflaumer (FLAU'-mer), and the Children's Alliance.