LA CROSSE, Wis. -- The fight over collective bargaining started in February 2011 with massive protests in Wisconsin's Capitol.

It eventually ignited a movement to recall Wisconsin's Governor Scott Walker, a Republican who took office at the start of 2011.

Nearly 16 months after the protests, the issue is still a large focus of the looming recall elections.

"I think collective bargaining was the match that started the prairie fire," said Milwaukee Mayor Tom Barrett, one of the Democratic candidates for governor.

Barrett and former Dane County Executive Kathleen Falk are the front-runners in the Democratic primary. They will also face off against State Sen. Kathleen Vinehout, Secretary of State Doug La Follette and protest-candidate Gladys Huber.

Barrett and Falk both say restoring collective bargaining will be a top priority if they're elected governor. However, they say the other's plan won't work.

Barrett argues there are several ways to restore the privilege of collective bargaining, including calling a special legislative session to force a vote on the issue.

"I think there will be members of the (State) Assembly that are Republicans who are going to look at that and say the landscape is a lot different than it was in March 2011," said Barrett, arguing there are even Republicans who would vote differently if they had another chance to do so.

Falk, on the other hands, says there's only one way to undo what Walker did. She has pledged, as governor, to veto any budget that does not immediately restore collective bargaining for all public employees.

"The only tool that a governor has to exercise is that veto power," said Falk.

"That's why it's important to elect a governor who is willing to go to the mat to restore collective bargaining," she added.

Barrett will not make the same budget veto pledge, arguing there's an inherent flaw with the idea.

"I think that's playing right into the Republicans hands," said Barrett.

"What would happen if there was no budget is that you would continue to operate as a state under the existing budget and the existing budget right now is Governor Walker's budget," he added.

Collective bargaining was passed into law in Wisconsin in 1959 to give unions and their membership an opportunity to negotiate things like wages, benefits and working conditions.

Governor Walker, who leads all Democrats in the latest poll, says taking away collective bargaining was needed to help balance the state's massive budget deficit.

He says it's a necessary tool for local governments and school districts to be able to offset all the money they've lost in state aid.

The recall primaries are on May 8. The general election will be on June 5.