Denver (AP) Opponents of an anti- proposal say they're filing a legal challenge to try to keep the proposal off this fall's ballot.
They're challenging the validity of more than 65,000 signatures collected by the proposal's backers.
Opponents say some signatures don't match the names in voter registration files and that some signatures appear twice. They also claim that some petitions were certified by notaries with expired commissions.
Backers collected about 129,000 signatures to get the issue on the ballot, about 50,000 more than required.
Colorado's proposal is backed by California businessman Ward Connerly, who has helped passed similar proposals in other states.