MADISON, Wis. - On a prank call that quickly spread across the Internet, Wisconsin Gov. Scott Walker was duped into discussing his strategy to cripple public employee unions, promising never to give in and joking that he would use a baseball bat in his office to go after political opponents.

Walker believed the caller was a conservative billionaire named David Koch, but it was actually the editor of a liberal online newspaper. The two talked for at least 20 minutes - a conversation in which the governor described several potential ways to pressure Democrats to return to the Statehouse and revealed that his supporters had considered secretly planting people in pro-union protest crowds to stir up trouble.

The call, which surfaced Wednesday, also showed Walker's cozy relationship with two billionaire brothers who have poured millions of dollars into conservative political causes, including Walker's campaign last year.

Walker compared his stand to that taken by President Ronald Reagan when he fired the nation's air-traffic controllers during a labor dispute in 1981.

"That was the first crack in the Berlin Wall and led to the fall of the Soviets," Walker said on the recording.

The audio was posted by the Buffalo Beast, a left-leaning website based in Buffalo, N.Y., and quickly went viral.

Ian Murphy told The Associated Press he carried out the prank to show how candidly Walker would speak with Koch even though, according to Democrats, he refuses to return their calls.

Murphy said he arranged the call Tuesday after speaking with two Walker aides, including the governor's chief of staff. He placed the call using Skype and recorded it.

Walker spokesman Cullen Werwie confirmed that it was Walker's voice on the call. At a news conference, Walker acknowledged being deceived but stuck to his message that the union changes were needed to balance Wisconsin's budget.

"I'm not going to let one prank phone call be a distraction from the job we have to do," Walker said. "The things I said are the things I've said publicly all the time."

On the call, the governor said he was ratcheting up the pressure on Senate Democrats to return to the Capitol a week after they fled to block the legislation. He said he supported a move to require them to come to the Capitol to pick up their paychecks rather than have the money deposited directly.

He also floated an idea to lure Democratic senators back to the Capitol for negotiations and then have the Senate quickly pass the bill while they are in talks.

Walker said aides were reviewing whether the GOP could hold a vote if Democrats were not physically in the Senate chamber but elsewhere in the building. At the news conference, he insisted that idea was not a trick but an effort to get Democrats back to work.

Democrats seized on Walker's recorded comments as evidence that the governor plans to go beyond budget cuts to crushing unions.

"This isn't about balancing the budget. This is about a political war," Rep. Jon Richards of Milwaukee yelled Wednesday on the floor of the state Assembly.

The governor's plan would strip most public employees of their collective bargaining rights and force them to pay more for their health care and retirement benefits. Unions could not collect mandatory dues and would be forced to conduct annual votes of their members to stay in existence.

The proposal has set off more than a week of protests at the Capitol.

The GOP-controlled state Assembly began debating the bill Tuesday and was still hearing dozens of Democratic amendments nearly 24 hours later before taking a break. Assembly Speaker Jeff Fitzgerald said he expected to take a vote on the bill by the end of the day.

Anti-union proposals in other states have also drawn protests, and Republican state senators in Ohio on Wednesday agreed to a small concession in a bill similar to the one in Wisconsin. They said they would support allowing unionized state employees to collectively bargain for wages - but not for benefits, sick time, vacation or other conditions. Wisconsin's proposal also would allow state workers to collectively bargain only for wages.

On the call, Walker said he expected the anti-union movement to spread across the country and he had spoken with the governors of Ohio and Nevada. The man pretending to be Koch seemed to agree, telling Walker, "You're the first domino."

"Yep, this is our moment," Walker responded.

The remarks showed Walker's private relationship with David Koch. He and his brother, Charles, own Koch Industries Inc., which is the largest privately-owned company in America and has significant operations in Wisconsin.

Its political action committee gave $43,000 to Walker's campaign, and David Koch gave $1 million to the Republican Governors' Association, which funded ads attacking Walker's opponent in last year's election.

The Kochs also give millions to support Americans For Prosperity, a conservative business group that launched a $320,000 television ad campaign in favor of Walker's legislation Wednesday. When the caller asked how he could help, Walker suggested outside groups could try to influence people to call their lawmakers and spread the message that his proposal is necessary.

On the recording, after Walker said he would be willing to meet with Democratic leaders, the caller said he should bring a baseball bat to negotiations.

Walker laughed and responded that he had "a slugger with my name on it."

The caller suggested he was thinking about "planting some troublemakers" among the protesters, and Walker said his administration had thought about doing that, too, but decided against it. Walker said the protests eventually would die because the media would stop covering them.

Walker told reporters the plan to bring in outside agitators was one of many ideas his supporters and aides have raised that were dismissed.

At the end of the call, the prankster says: "I'll tell you what, Scott, once you crush these bastards, I'll fly you out to Cali and really show you a good time."

"All right, that would be outstanding," Walker replies, adding that the standoff is "all about getting our freedoms back."

The caller responds: "Absolutely. And you know, we have a little bit of vested interest as well" and laughs.

Walker's budget bill also allows his administration to sell power plants that heat and cool state buildings to private companies without any bids.

Critics have seized on that provision, saying they are convinced the Koch brothers' business interests would be able to buy power plants on the cheap, and then profit by running them and driving up the price of energy.

Koch Industries has denied any interest in buying the plants. Republicans tried to privatize Wisconsin's power plants in 2005, but the plan was vetoed by Democratic Gov. Jim Doyle.

Immediately after taking office, Walker also pushed for legislation that would limit damage awards in lawsuits against many businesses.

Koch Industries lobbied for the bill, and Walker signed it into law last month. Walker is also seeking passage for another Koch Industries-backed bill to weaken state regulations by giving him the power to approve all rules proposed by agencies, a proposal that is moving quickly through the Legislature.

Koch Industries recently opened a lobbying office a block from the Capitol. Seven lobbyists have registered in Wisconsin to lobby for various Koch Industries companies.

Even before recordings of the call surfaced, the government watchdog group Common Cause in Wisconsin released a statement saying Walker's agenda matched with that of Koch Industries.

"Koch Industries and other corporate citizens have legitimate interests in Wisconsin, but their demonstrated willingness to push large amounts of money into state politics has given them a dangerously outsized voice," said Bob Edgar, the group's national president. That voice, he said, is "now demanding a return on its investments."