(CNSNews.com) - The Obama White House says it doesn't matter who Republican Mitt Romney chooses as his running mate: "We are closely watching," Obama campaign spokeswoman Jen Psaki told reporters accompanying President Obama to Colorado on Wednesday.

"We don’t know any more than you do about the day and who it will be.  And as soon as he picks, we’re happy to tell you why that person may be a bad choice for middle-class families."

Psaki said the Obama campaign thinks it "would be an excellent choice" for Romney to pick Newt Gingrich or Michelle Bachmann:

"I'll also add that any way you cut it, whomever we pick, we'd much rather have Vice President Biden on our side campaigning across the country, in the debates, out there standing up for the President than any of the motley crew that Mitt Romney is choosing between."

The gaffe-prone Joe Biden, a longtime Washington insider, is playing up his blue collar, Scanton roots on the campaign trail, blasting Romney as someone with a Swiss bank account who is out of touch with the middle class.

The Hill newspaper reported that Romney's wife Ann tweeted Wednesday afternoon that "Mitt's choice for VP will be announced soon."

Even before the announcement happens, Democrats already are disparaging likely Republican running mates.

As the Associated Press reported, "The president's campaign started swinging at the potential Republican running mates this week while urging home-state Democrats to chime in about the shortcomings that — as emails to donors and supporters put it — 'Americans need to know.' The pre-emptive strikes are an effort to define a possible No. 2 in a negative light..."

The AP also noted that American Bridge 21st Century, a Washington-based super PAC, already has dumped a combined 1,651 unflattering pages of opposition research on Republicans Tim Pawlenty, Rob Portman, Marco Rubio, Bobby Jindal and Paul Ryan:

"The five electronic briefing books, including two released Wednesday, rake over the Republicans' voting records, proposals, public statements and slipups. The rundowns are so detailed that a politician's taste for expensive wine is even noted in one of the books," AP said.

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