A group opposing a November ballot initiative to change Michigan's redistricting process has launched a radio ad that calls Proposal 2 a "blank check" for a commission of 13 people that would draw congressional and legislative lines once a decade.
The ad announced Thursday is the first spending by conservatives to sway voters.
They previously focused on knocking the measure off the ballot.
The ad financed by Protect My Vote says the constitutional amendment would "cost you an insane amount of money" because there would be "no limits" on the commission's hiring of staff and consultants.
Proposal 2 backers are running TV and digital ads. Voters Not Politicians calls the opposition radio spot a "desperate attempt" by politicians, lobbyists and special interests to protect power and continue rigging election maps.