ST. PAUL, Minn. - Last year's emotional campaign over a proposed Minnesota gay marriage ban cost the two main competing groups a combined $18 million, according to campaign finance reports released Friday.

That made it Minnesota's most costly election, although spending on the failed state constitutional amendment was just a slice of the millions consumed by all the races on the ballot.

Minnesotans United for All Families, the leading group on the winning side, spent about $12.4 million last year. It was far more than the $5.6 million that Minnesota for Marriage put into its effort, at least one-fifth of that from the Catholic church. The total spending on the ballot question climbs even higher when campaign activity from 2011 and by other groups is included.

Those dollars fueled a highly visible campaign waged with television advertising, leaflets, bumper stickers, billboards and door-to-door canvassers.

Richard Carlbom, who managed the anti-amendment campaign, said his group knew at the outset it would take more than $10 million to win given that voters in other states had yet to reject a gay marriage ban. He said the organization's 80,000 contributors and 250,000 email addresses will pay dividends as Minnesota lawmakers now debate whether to legalize gay marriage.

"There are literally tens of thousands of engaged volunteers who are trained on how to have deeply personal and authentic conversations about why marriage matters," Carlbom said. "That is a carryover."

Autumn Leva, a spokeswoman for Minnesota for Marriage, said disclosure requirements hindered its fundraising efforts because some people and businesses didn't want to donate if their names were made public.

Leva said the campaign's volunteers and faith leaders remain "ready to get back in the action" when the marriage issue comes up again at the Capitol. "None of that time or money was wasted in the campaign. We are thankful to have that structure still in place," she said.

Supporters of same-sex marriage want lawmakers to vote this year on a legalization bill, although Carlbom's group acknowledged in a fundraising email this week that they probably lack the votes to change the law at this point. Democrats control both legislative chambers and Gov. Mark Dayton supports the cause, but some Democratic lawmakers represent districts where most voters backed the gay marriage ban. Some suburban Republican legislators also face a conundrum because their constituents largely opposed the amendment.

Rep. Jenifer Loon, R-Eden Prairie, is one of them. She said Friday that she hasn't decided how she would vote on a bill to allow gay marriage.

"This is a leap from the vote that was made. I need to do a lot more talking with the folks in my district about what this would mean and what they are supportive of," Loon said. "I'm still looking at this issue and I don't have a position at this point."

There also was a multimillion dollar campaign surrounding the other constitutional amendment that voters rejected. It would have required people to present photo IDs to vote.

Our Vote Our Future, the leading voice against the amendment, spent $3.2 million on its campaign and still owes vendors $650,000 of that. On the other side, ProtectMyVote reported running a nearly $1.5 million campaign.

Other highlights from the new campaign reports:

_Democratic Gov. Mark Dayton, who says he intends to seek a second term in 2014, entered the year with about $95,000 in the bank, a low figure compared to the last incumbent at this stage. Dayton loaned his campaign about $3.9 million in 2010 and almost all of that debt is still on the books. He said he will ramp up fundraising after the legislative session but didn't rule out more personal loans. "I really have not thought much about the whole enterprise at this point," he told reporters. "But I do accept I have to do everything possible legally and ethically to win, so we'll see."

_Democrats who claimed control of the House and Senate outspent the Republican caucuses they displaced from power. The political committees for the four legislative caucuses spent nearly $12 million combined. That doesn't count money candidates spent on their individual races.

_Outside groups again played a powerful role in state legislative campaigns. The Alliance for A Better Minnesota, which aided Democrats, led the way with $3.7 million in spending. On the GOP side, the Freedom Club State PAC plunked down $1.9 million.


Associated Press writer Patrick Condon contributed to this report.