Senate Democrats announced Tuesday the most comprehensive campaign finance legislation in the last two decades will be sent back to committee.

The decision to hold the bill came after Gov. Scott McCallum refused to promise lawmakers he would not use partial veto power on any campaign finance bill with which he was presented.

The state Senate tentatively approved the bill last week, but Senate Majority Leader Chuck Chvala, D-Madison, said final approval for the bill depended on the governor promising not to use his veto power to alter the bill.

Sending the bill back to committee does not kill the proposal, but it exposes the bill to more amendments that could affect the bipartisan balance agreed upon by Chvala and Assembly Speaker Scott Jensen, R-Waukesha.

The bill would increase the amount of public money available for candidates for state office in exchange for abiding by voluntary caps in campaign spending. The plan would also control the influence of special interest groups by matching grant money given to candidates by the groups.

McCallum said he would not use partial veto power but would not promise to give up all veto rights.

In the Republican-controlled Assembly, Jensen asked Democratic Attorney General Jim Doyle to ensure the plan was constitutional before it became legislation.

Jensen’s spokesman, Steve Baas, said the bill has essentially been killed.

“The governor has said he wants campaign finance, but he won’t surrender his veto authority,” Baas said. “This is asking him to commit to not veto things that might not even be in the bill at this point.”

Baas said the legislature is working on an alternative campaign finance reform bill to be introduced later this month.