The Obama campaign launched a pre-emptive strike Tuesday on Florida Sen. Marco Rubio, attempting to gather dirt on the potential vice presidential pick by asking Floridians to share with the campaign “the good, bad and ugly” about him.

Ashley Walker, director of Obama for America in Florida, blasted out the email Tuesday soliciting unflattering information on Rubio.

“Share what you think the rest of the country should know about what Rubio’s really done in Florida,” Walker wrote, “the good, bad and ugly. And why he’d be a disaster as our next vice president.”

The effort marks a new phase in the Obama campaign's push to undermine Romney's highly anticipated selection of a running mate. That selection could come any moment, and Republicans have been building anticipation in recent days by announcing, a few at a time, the speakers for the GOP convention. It is presumed that whoever is on the convention speakers list at this point is no longer being considered for Mitt Romney's ticket.

Rubio, who so far is not on the convention speakers list, appears to be a finalist on Romney’s list for a running mate, with less than three weeks remaining before the party’s national convention in Tampa, Fla.

The first-term senator and Tea Party favorite will join Romney in the Florida leg of his “The Romney Plan for a Stronger Middle Class" bus tour that starts this weekend.

Two other potential Romney running mates also will be on the tour. Virginia Gov. Bob McDonnell will join when the tour begins Saturday in his home state. And Ohio Sen. Rob Portman will join when the tour concludes Tuesday in his state.

Rubio will join when the bus arrives Monday in Florida.

“We know Marco Rubio all the way from his time in the Florida House of Representatives to his election to the U.S. Senate,” Walker continued. “But most Americans don't know him or the extreme, tried-and-failed policies he'd bring with him to a Romney administration. As Floridians, it's our job to share what we know about Marco Rubio with the rest of Americans. Your feedback will help hold Rubio accountable, if and when Romney chooses him.”

In the letter, Walker also accuses Rubio when in the Florida legislature of balancing the state budget by “sticking it to the middle class” and in Congress of leading the way “on almost every extreme position Mitt Romney has embraced.”

The Obama campaign also reportedly sent out a similar letter in Ohio regarding Portman.

“If and when Romney does select him, we need to be able to tell the full story about his record on Day One, which could very well be in the next few days,” according to the letter, reported by Politico. “As one of the architects of the top-down Bush budget, Portman practically invented the policies that punished middle-class families while exploding the deficit, and crashing our economy. ... Let's make sure we're ready.”