WASHINGTON — With less than three weeks to go until the Republican National Convention, Mitt Romney’s choice of running mate is expected any day now — and there’s little expectation of a Sarah Palin-esque “game-changer” waiting in the wings.

Romney was campaigning Thursday in the battleground state of Colorado with a handful of Republican governors, including three potential vice-presidential picks — Louisiana’s Bobby Jindal, New Jersey’s Chris Christie and Bob McDonnell of Virginia.

Speculation that a VP announcement is imminent roared into overdrive when Politico.com reported that Beth Myers, a longtime Romney adviser heading up the search for his running mate, is travelling with the Republican presidential hopeful.

In recent days, Team Romney has also reportedly bulked up the team of campaign aides tasked with working with his running mate, who’s widely expected to be a safe, exhaustively vetted No.2 for the famously risk-averse candidate.

By most accounts, memories of John McCain’s ill-fated pick of Sarah Palin four years ago are still fresh in the minds of Romney and his brain trust.

Even Dick Cheney, George W. Bush’s controversial vice-president, recently urged the campaign not to make the same “mistake” McCain did in 2008 when he sought to shake up the race by choosing the inexperienced, barely vetted but energetic Palin.

In a weekend interview with ABC News, Cheney said Palin failed to meet the most important requirement for a vice-president: a preparedness to step into the presidency if need be.

“Based on her background — she was only governor for two years, I don’t think she passed that test of being ready to take over. And I think that was a mistake,” Cheney said.

In a meandering rebuttal, Palin pushed back against the charges, alluding to the famous 2006 incident in which Cheney accidentally shot a campaign contributor while hunting quail.

“Seeing as how Dick — excuse me, vice-president Cheney — never misfires, then evidently he’s quite convinced that what he had evidently read about me by the lamestream media, having been written, what I believe is a false narrative over the last four years,” Palin said on Fox News on Wednesday.

But Republican strategist Matt Mackowiak says Palin is most certainly looming large over the Romney campaign as they carefully consider the candidate’s potential running mates.

“There’s no question that how her nomination affected that race, particularly in terms of media coverage, has cast an enormous shadow over this choice for Romney,” Matt Mackowiak said in an interview Thursday.

“I don’t think it’s necessarily fair, because their situations are entirely different — John McCain was down by a touchdown with two seconds to go and and he decided to throw a Hail Mary pass, and then everyone got mad that the receiver couldn’t complete the pass.”

Romney, however, is running neck-and-neck nationally with Obama, and says he wants to keep the focus on the president and his economic policies instead of introducing a potentially distracting big personality into the race.

For that reason, Mackowiak added, Romney will likely choose from one of two relatively bland but squeaky-clean politicians: Tim Pawlenty or Rob Portman.

Portman, a junior U.S. senator from Ohio, apparently sought to distance himself from the Bush/Cheney years in an interview published Thursday in the congressional newspaper The Hill.