Governor Patrick Quinn (D-IL) Wednesday expressed concern over his running-mate’s history of domestic violence, telling reporters that the Democrats’ nominee for lieutenant governor “should step aside,” barring a compelling explanation for his actions.

Scott Lee Cohen, who allegedly threatened his prostitute girlfriend by brandishing a knife and throwing her against a wall, Tuesday won the Democratic Party’s nomination for lieutenant governor, edging out five other contenders in an upset victory.

Quinn met with state Democratic Chair Mike Madigan to discuss the news of Cohen’s 2005 arrest, but refused to say publicly if he or Madigan had resolved on a contingency plan in the event Cohen voluntarily steps aside, the Chicago Sun-Times reports.

Democrats are said to have launched a campaign within the state party apparatus to compel Cohen not to seek office, if only to ensure the governorship remains in Democratic hands.

Asked if he would run as a third-party candidate in the event Cohen ignores the counsel of Illinois Democratic operatives, Quinn said only that “the situation will resolve itself,” hinting that Cohen will forgo the campaign.

The office Cohen aims to fill has remained vacant since January 2009, when then-Lieutenant Governor Quinn succeeded disgraced and now-impeached Rod Blagojevich.

UPDATE: While Governor Quinn and influential state Democrats are nudging–forcefully pushing, on some counts–Cohen to drop out of the race, the Democratic nominee for lieutenant governor said no dice.

“I have no intention of stepping down or stepping aside,” Quinn said in a strongly-worded statement today. “When the facts come to light, after my ex-wife and ex-girlfriend speak, the people of Illinois can decide, and I will listen to them directly.”

But whatever the people of Illinois decide, it’s clear the people of the Illinois Democratic Party have reached resounding consensus: Cohen is a unnecessary burden to Democrats in what most election handicappers project will be a hostile election cycle.

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