MADISON, Wisconsin (Reuters) - The Wisconsin state Assembly early on Friday passed a Republican plan to curb public sector union power, setting up a showdown with Senate Democrats who fled the state last week to prevent a vote.

Tens of thousands of demonstrators, from inside and outside the state, have converged on Madison in the past two weeks to fight the proposal, which they fear could encourage similar measures in other states and cripple the American labor movement. Another big protest is scheduled for Saturday.

After debating the proposal into a third consecutive night, the Republican-dominated Assembly abruptly ended all debate before dawn on Friday morning and approved the bill by a vote of 51 to 17.

Republican Gov. Scott Walker has said approval of the plan is vital by Friday for Wisconsin to prepare a restructuring of outstanding debt to help eliminate the current budget deficit. He also has threatened immediate layoffs without approval.

While the deadline was met in the Assembly, it was not clear what would happen in the Senate, where the absence of Democrats has and will continue to prevent a vote.

Walker commended fellow Republicans for the vote he said would fix the budget for this fiscal year and future budgets.

"Now all the attention is on the Senate," Walker said in a statement. "The fourteen Senate Democrats need to come home and do their jobs, just like the Assembly Democrats did."

Republicans hold a 19-14 Senate majority but need a quorum of 20 to vote on spending bills. All the Democrats left the state for Illinois last Thursday because they feared they could be compelled to attend the Senate if they remained.

Wisconsin Republicans sent police on Thursday on an unsuccessful search for the runaways. But Republican leaders have said they lack the power to force the Democrats back in.

In an interview on Friday for the program "Democracy Now," state Senator Chris Larson, one the 14 lawmakers who fled the state last week, said he and his Democratic colleagues had no intention of returning to Wisconsin any time soon.

"Until we are able to engage in a real debate, until we're able to throw this bill out and actually move forward with a budget repair bill and move forward with the real business of Wisconsin, we can't come back," Larson said.

"We saw what happened in the Assembly late last night," Larson said, "and it's just unacceptable.

The outcome of the Assembly vote, which was taken so fast many Democratic lawmakers were outside the chamber when it was called and were unable to participate, was greeted by chants of "it's not over yet" and "we are here to stay" from more than a thousand protesters camped out in the Capitol.


Democratic lawmakers and unionized public employees said the Walker plan is an attempt to bust the unions and choke off funding to organized labor, the largest source of funding to the Democratic Party.

If Republicans prevail in Wisconsin, efforts could speed up in other states to take on powerful public unions. Wisconsin-inspired curbs on union rights have been debated in the legislatures of other states including Indiana, Ohio, Iowa, Tennessee and Kansas.

U.S. state and local governments are struggling to balance budgets after the recession decimated their finances. Other states like Texas, Arizona and Ohio are relying mainly on cuts in spending, while Minnesota and Illinois are raising taxes.

The Wisconsin changes sought by Walker would make state workers contribute more to health insurance and pensions, end government collection of union dues, let workers opt out of unions and require unions to hold recertification votes every year. Collective bargaining would be allowed only on wage increases up to the rate of inflation.

Representative Cory Mason, a Racine Democrat, told assembled protesters in the state Capitol overnight he believed the abrupt late-night vote, which occurred while several Democrats waited to be heard on the measure, was "a violation of the rules, possibly a violation of the law."

"What happened tonight, for those of you who don't know, was unprecedented," Mason said. "They're so desperate to take away workers' (rights) they will do anything to ram this through." He said the move would "backfire" on Republicans.

(Writing by Greg McCune. Reporting by James Kelleher and Jeff Mayers. Editing by Will Dunham and Peter Bohan)