July 7 (Bloomberg) -- The prerequisites for John McCain's running mate are clear: a Washington outsider with solid economic credentials who isn't associated with President George W. Bush, can fill the vice-presidential attack-dog role, help win Western and Midwestern states and cut into Democrat Barack Obama's fundraising advantage.

One candidate fits the bill: former Massachusetts Governor Mitt Romney.

The challenge would be in overcoming the animus that set in between Romney and the presumptive Republican nominee during the party's primaries.

Romney, 61, has ``no shortage of strengths,'' said Dan Schnur, who was McCain's communications director in 2000.

At the same time, though, ``McCain is a very visceral politician; he has very strong reactions both to people who he personally likes and dislikes,'' Schnur said. ``It was pretty apparent during the primary that he and Governor Romney did not hold each other in very high regard.''

Romney had a successful career as a private-equity executive, has never lived in Washington or held national public office, and his ties to the Mormon community and the business world give him access to donors.

Mormon Support

In addition, he was born in Michigan where his father was governor, and beat McCain by nine percentage points in the state's primary this year. Romney also has strong support in Western states such as Nevada, where his fellow Mormons made up a quarter of the voters in the state's January Republican primary, according to exit polls.

During the primary, Romney proved he was capable of going on the attack, a skill that is required of vice presidential candidates. McCain felt the sting of that aggressive streak before the Jan. 15 Michigan primary, when Romney characterized his comments about the state's job losses as a demonstration of ``pessimism about Michigan's future.''

On substance, Romney is strong in areas where Arizona Senator McCain is weak, in particular the economy. McCain, 71, said in December that he doesn't understand economics ``as well as I should'' and his lack of comfort is apparent on the stump.

Private-Equity Background

When asked in April about reversing his support for a federal home-mortgage bailout, he reached for a sheet of talking points. By contrast, Romney has a master's of business administration from Harvard University, ran the 2002 Salt Lake City Olympics, and made a vast fortune as co-founder of the Boston-based private-equity firm Bain Capital LLC.

A report last week in Politico.com that Romney could raise $50 million in 60 days is also feeding speculation that he is at the top of McCain's list.

Ron Kaufman, a political director in President George H.W. Bush's administration and a Romney campaign adviser, said the former Massachusetts governor is getting a close look as the economy displaces the war in Iraq as the most pressing concern for Americans.

``It's more about gas prices than fundraising and it's more about the economy not doing so well than anything else,'' Kaufman said. ``The most logical person in anyone's mind is Mitt Romney.''

For the moment, however, it is unclear whether these assets would be enough to overcome the residual bad feeling from a bitterly contested primary.

`Didn't Do Good'

``He beat the daylights out of us and certainly out of McCain,'' said Ed Rollins, the campaign chairman for former Arkansas Governor Mike Huckabee, who also ran for the Republican nomination. ``He spent the most money, attacked everybody more and at the end didn't do good.''

Romney also brings negatives, including his Mormon religion, which some of the evangelicals who form a core Republican constituency describe as a cult and a disqualifier for their support. They also have condemned what they regard as his shifting positions on issues such as gay rights and abortion.

``There's a lot of stuff out there that won't stand scrutiny,'' Rollins said.

That weakness plays into one of the biggest vulnerabilities of McCain, who is trying to mend fences with the Christian right after years of frayed relations. Last month, he met with the evangelist Billy Graham and a group of prominent Ohio Christian leaders.

Oversaw Layoffs

Schnur said Romney's apparent advantage on the economy may have a down side. During his unsuccessful 1994 run against incumbent Democrat Ted Kennedy for a Massachusetts Senate seat, Romney was criticized for overseeing layoffs while working at Bain.

``The Democrats could have a heyday talking about downsizing and lay-offs,'' Schnur said. ``It's the type of thing that in a difficult economic climate could be a real problem.''

Still, Romney is battle-tested and well-known, and has support in the fiscal-conservative wing of the Republican Party.

Neither McCain nor Romney have publicly discussed the possibility of a shared ticket. In May, however, the former Massachusetts governor was a guest at McCain's ranch in Sedona, Arizona, along with potential vice presidential nominees such as Florida Governor Charlie Crist and Louisiana Governor Bobby Jindal.

McCain's second-tier advisers have been arguing for Romney ``for a long time,'' said Vin Weber, who was Romney's policy chairman on the campaign. For the moment, though, ``I still don't see any evidence we have anyone'' in McCain's inner circle making the case.

To contact the reporter on this story: Heidi Przybyla in Washington at hprzybyla@bloomberg.net.

Last Updated: July 7, 2008 00:01 EDT