MADISON, Wis. — Senate Democrats on Thursday night delayed a vote on passing the state budget until early Friday morning, following 12 hours of debate in which all of their amendments were rejected by Republicans.

Republicans had the votes to pass the budget after securing the support of a key moderate, but another Republican's announcement that he would join Democrats in opposing it gave the GOP just a one-vote margin.

Sen. Rob Cowles, one of the most vocal Republican critics of the $70 million spending plan, told The Associated Press he would vote for it. Republican Sen. Dale Schultz said he would side with Democrats against it, leaving the GOP with just a 17-16 margin.

The budget would cut income taxes $650 million, expand private voucher schools statewide and reject a federally funded expansion of Medicaid. It sets funding for public schools, requiring collection of DNA for anyone convicted of a crime, and allowing the sale of public properties.

Schultz, of Richland Center, said during the debate he was voting against the budget because it was "too far removed from representing the interests of the common men and women I represent."

Schultz said the voucher school expansion put the state on a path toward creating a parallel school system that will take money from public schools.

"We can't adequately support one statewide school system. Why on earth would we create a second?" Schultz said. "It just makes no sense. At best we are creating nothing more than another middle-class entitlement program. How's that conservative?"

Schultz also criticized other parts of the budget, including the creation of a bail bondsmen program and banning the Center for Investigative Journalism from operating on the University of Wisconsin-Madison campus.

Schultz hasn't said whether he will seek re-election, but conservative Republican Rep. Howard Marklein has announced he will seek the seat next year. Marklein was one of three Republicans who voted against the budget in the Assembly.

Senate debate came after the Assembly on Wednesday adopted more than two dozen last-minute changes to the plan, many of which had been negotiated to help ease passage in the Senate.

While the Senate spent 12 hours on the bill, Assembly Democrats offered not to amend it or prolong debate. It passed the Assembly in a little over an hour.

Sen. Alberta Darling, the Republican-co chair of the committee that crafted the budget plan up for debate, said it puts Wisconsin on the right path toward creating jobs, protecting the poor and putting more money in people's pockets.

"We are definitely in a better position than we were two years ago," Darling said. "Two years from now I predict we will be in a much better position than we are today."

But Democratic Sen. Jen Shilling said the budget was a "roadmap to mediocrity."

"This budget doubles down on the failed policies of the past," she said.

Democratic Minority Leader Chris Larson said members of his party planned to offer dozens of amendments to persuade Republicans to support changes that get to the heart of the biggest issues in the GOP-written proposal.

Those include eliminating the voucher school expansion, changing the income tax cut to benefit lower-wage earners, accepting federal money to expand Medicaid and spending more on schools. Democrats also proposed spending more on worker training programs, eliminating a projected budget shortfall in four years and disallowing the sale of public properties.

Larson even brought in his welcome mat from home and put it in front of his office door as a symbolic gesture for Republicans to join Democrats.

"Together we can make this budget better. You just have to walk through the door," Larson said at a news conference.

Budget debate was interrupted briefly by what appeared to be a coordinated demonstration, with protesters shouting from the galleries and attempting to storm the floor. They were shouting, "Focus on jobs, not vaginas!"

The Senate earlier this month passed a bill requiring women seeking abortions to first have an ultrasound. Debate continued as police removed the demonstrators, several of whom continued screaming outside the chamber doors.

Eight people were ticketed for disorderly conduct, said Department of Administration spokeswoman Stephanie Marquis.