Liberals got what they wanted -- on June 5, Wisconsin Gov. Scott Walker will face a recall election. The problem is, before that can happen, Democrats need to settle on a candidate. With a primary set for May 8, Democrats will only have four weeks to heal whatever wounds get opened during the primary and unite to challenge Walker. Thus far, the primary is looking like it will be divisive if not nasty.

Over at Talking Points Memo, Eric Kleefeld has a report on the contentious battle for the Democratic nomination, with the two leading candidates being Dane County Executive Kathleen Falk and Milwaukee Mayor Tom Barrett, who lost the governor’s race to Walker in 2010.

Falk has the support of two major unions: the American Federation of State, County and Municipal Employees (AFSCME) and the teachers’ union, the Wisconsin Education Association Council. Interestingly, WEAC endorsed Falk without even polling its members.

AFSCME made waves last week when it circulated audio suggesting that Barrett supported Walker’s public sector union reforms. Though the union now says it used “poor judgment” in promoting the “over the top” video, it still argues that Barrett has a bad record on collective bargaining issues, claiming that he demanded too many concessions in negotiations with the union as mayor.

Also, Falk has taken a harder line in vowing to veto any budget that did not repeal Walker’s public sector union reforms, which would effectively force a government shut down. Barrett isn’t quite ready to go that far, arguing that he’d call a special session of the legislature and work with Republicans to pull back the reforms.

Former Democratic Congressman David Obey, endorsing Barrett, blasted AFSCME, saying that, “blaming Tom Barett for actions in the Milwaukee budget that were forced by Governor Walker is like blaming surgeon who does surgery on a patient after he is hit by a truck." (Via WisPolitics.com)

Obviously, there are always different schools of thought as to whether a tough primary strengthens or weakens a nominee. If the primary merely is an argument about who is more opposed to Walker, it may not hurt Democrats and could perhaps even help. For instance, if Barrett wins the primary and emerges looking more moderate than Falk – as somebody who is less beholden to unions and more willing to work with the Republican-controlled legislature – it could help with swing voters. But if the primary starts to get more personal and drives up each candidates’ negatives, it may be harder to recover in the mere four weeks before the recall election against Walker.