A Senate panel's surprise vote Wednesday to authorize racinos as a way to fund a new Minnesota Vikings stadium left project backers scrambling to erase the proposal before it could scuttle the stadium effort.

The racino addition approved by the Senate Finance Committee was another indicator that many legislators remain doubtful that the state's $398 million share of the $1 billion stadium can be funded solely by allowing electronic bingo and pulltabs in Minnesota bars and restaurants.

Senate Republicans spent much of the day mounting a vigorous challenge to the stadium plan, warning that state taxpayers could ultimately have to pay for the project and arguing that the stadium's large public subsidy went against the party's conservative principles.

The racino plan, to authorize slot machines at the state's horse racing tracks, could disappear as soon as Thursday, when the stadium plan goes before the Senate Taxes Committee, but its emergence Wednesday afternoon left stadium backers concerned.

"I'm in trouble with racino going onto the bill," said Sen. Julie Rosen, R-Fairmont, the chief Senate stadium author.

Adding slots to the state's horse tracks has never been a winner among legislators and Indian tribes that operate casinos in Minnesota. On Wednesday, DFLers said to expect no help from them if the racino provision remained. "You'll have almost no votes from the [DFL] caucus," said Sen. Richard Cohen, DFL-St. Paul.

The day's events appeared to slow -- but not halt -- momentum for the stadium, which had earlier received a boost when Vikings star running back Adrian Peterson made a surprise visit to the State Capitol. With the Legislature moving to adjourn as early as Monday, a House floor vote was pushed back at least a day.

Stadium backers had prevailed through much of the daylong Senate hearing Wednesday, successfully eliminating an attempt to tie building the stadium in Minneapolis to providing more funding for St. Paul projects and also beating back an idea to impose a statewide 5-cent-a-drink liquor tax to fund the project.

But it seemed that even as one potential stumbling block was averted, another took its place. House Speaker Kurt Zellers, who has not taken a position on the stadium, appeared to up the political ante Wednesday for the project, saying that the DFL House minority would have to provide half of the 68 House votes to approve the stadium, even though Republicans hold a 72-61 majority.

"I'm concerned it's getting heavy, it's getting complicated," Vikings spokesman Lester Bagley said of the attempts to change the plan. "We've got five days left, and the more complicated it gets, the harder it's going to be to get done."

The day's stadium drama at the Capitol was highlighted when Peterson and Vikings teammates John Sullivan and Chad Greenway visited legislators and were immediately surrounded by TV cameras as they walked through the rotunda.

"You're a stud, man," one boy called out as Peterson waded into a crowd of schoolchildren touring the Capitol.

During one moment, as cameras recorded the event, Sen. John Howe, R-Red Wing, a key member of the Senate Taxes Committee, was invited to ride on a Capitol elevator with Peterson and the other players.

There were plenty of other surprises Wednesday, too. The Senate Taxes Committee chairwoman suddenly asked that the project go before her panel, sending stadium supporters scrambling to assess the political implications of the move. Senate Majority Leader Dave Senjem, R-Rochester, however, predicted the project would survive a committee vote.

"It'll be fine," Senjem said. "We've got the votes in Taxes."

But conservatives in the Republican-controlled Senate were clearly trying to at least slow the stadium plan.

"The 2010 election, it seems to me, was pretty clear," said Sen. Dave Thompson, R-Lakeville, a leading Senate conservative. "People wanted things to be done a different way -- a different way being scaling back government and its influence in our lives."

Thompson, however, acknowledged that the stadium push at the State Capitol was being led by Republicans, including Rosen.

"I like to say that you kind of pit 'Country Club Republicans' against 'Limited Government Republicans' -- like me," he said.

Under the stadium plan, the Vikings would contribute $427 million to the project, the state would add $398 million and Minneapolis would provide $150 million to the stadium's construction. The team would also add $327 million over time to the stadium's operating costs, and the city would add $189 million.

"I feel like we have been watching a very hard fought, great game, with the Vikings marching down to the goal line," said Eric Grubman, a National Football League executive vice president, after watching the stadium debate at the State Capitol. "And I feel like they're very close. And I think when it's very close, it gets really tough."

Staff writer Rachel E. Stassen-Berger contributed to this report. mkaszuba@startribune.com • 651-925-5045 jim.ragsdale@startribune • 651-925-5042