UPDATE 3:55 p.m. PST:  The 14 Wisconsin Democratic state senators who left the state to avoid a vote on the anti-union bill have been located at the Best Western Clock Tower Resort in Rockford Illinois.

Radio station WTMJ reported:

Law enforcement officials have been looking for at least one Democratic senator to bring in for a quorum required for a fiscal measure, but Democratic Senator Jon Erpenbach confirmed to Newsradio 620 WTMJ that he and all of his Democratic colleagues boarded a bus and left the state.

"We're not in Wisconsin right now," Erpenbach said.  "The reason why we're doing this is because there are some jurisdictional issues that we'd be dealing with."

The Senate's Sergeant at Arms cannot compel Senators' attendance in an open session if they are outside of state lines.

 Wisconsin's 14 Democratic lawmakers have left the state Thursday after failing to show up for a vote on sweeping new legislation that would force state workers to pay more for their pension and health benefits while limiting their bargaining rights. CNN is reporting that a total of 16 state senators were absent from the vote. 

Wisconsin State Capitol building (creative commons)

According to WisPolitics.com, Sen. Jon Erpenbach said he and his colleagues left the state in an effort to force Republicans to negotiate a compromise on the proposed bill.

"This isn’t anything that we do lightly at all. This isn’t a prank. This isn’t a joke. This is Democrats standing together saying slow down," Erpenbach told WisPolitics.com.

Senate Minority Leader Mark Miller said they were "trying to allow opportunity for democracy to work."

Erpenbach also did not say how long he and his fellow Democrats were prepared to stay outside the state. "The question is when are the Republicans going to sit down seriously with the other side on this issue and try to work something out," he said.

Miller added: ""We will return and do our job, but the governor has to do his job." 

Republican Gov. Scott Walker released a written statement blasting the Democrats for leaving the state.

"I am calling on Senate Democrats to show up to work today, debate legislation and cast their vote," Walker said. "Their actions by leaving the state and hiding from voting are disrespectful to the hundreds of thousands of public employees who showed up to work today and the millions of taxpayers they represent."

WisPolitics.com reported that state Senate Majority Leader Scott Fitzgerald said that Republicans will use the State Patrol to round up the lawmakers who failed to show up for the vote and bring them to the floor. As TPM noted, however, since the lawmakers left they state, they are presumably out of the state's jurisdiction. TPM also pointed out that the new head of the Wisconsin State Patrol happens to be Fitzgerald's father.

The situation in Madison, Wisconsin has intensified as Republicans look to bring the anti-union legislation to a vote on the floor. On Thursday, a reported 25,000 workers flooded the State Capitol in Madison to protest the legislation, chanting "This is our house" and "Forward not backward."

Rep. Paul Ryan (R-WI) said: "[It's] like Cairo has moved to Madison these days."