Governor McCallum's political opponents want him to do away with parts of a plan to reform campaign financing.
The budget repair bill on the governor's desk includes a campaign finance reform provision.
U.S. Representative Tom Barrett and Dane County Executive Kathleen Falk say McCallum should veto only a provision in the reform package that would nix the whole thing if a court found any part of it unconstitutional.
Attorney General Jim Doyle wants McCallum to veto the entire thing. He calls it a sham.
Barrett, Doyle and Falk all are running for governor.
Thirteen other lawmakers sent McCallum a letter Wednesday urging him to veto the clause that would do away with the whole package if portions are found unconstitutional.