WASHINGTON - Four years ago, Tim Pawlenty and Mitt Romney were rivals, fighting to be Sen. John McCain's presidential running mate. Staying up late one night with his wife, Mary, poring over personal records in their Eagan home, Pawlenty cracked, "No way is Mitt Romney doing this by himself."

One year ago, Pawlenty and Romney were slugging it out on the presidential campaign trail, with Pawlenty taking potshots at Romney's money and record.

Now, Romney is the presumptive GOP nominee for president. And Pawlenty? He's back on the inside track for the No. 2 spot.

Pawlenty, one of the first ex-candidates to throw his support to Romney, suddenly finds himself ranked near the top of every shortlist being compiled by top Romney aides, Republican operatives and seasoned political observers.

"Pawlenty is on the super-short list," said one GOP strategist with connections to the Romney campaign.

For Pawlenty, 51, the national attention is a resurgence from the humiliation of a third-place finish in last summer's Iowa straw poll that cut short his two-year quest for the White House.

But that experience also makes Pawlenty a battle-tested contender for a GOP campaign that feels no need to take chances against President Obama, a spark for Republican anger who is at the helm of a still-sputtering economy.

"At this point, where the race is right now, Mitt Romney does not need a game-changer," said Minnesota GOP consultant Ben Golnik, who worked for a McCain campaign that gambled and lost on Sarah Palin in 2008.

Pawlenty critics say he lacks the pizzazz of others said to be under consideration, such as New Jersey Gov. Chris Christie and Florida Sen. Marco Rubio. But some analysts say Pawlenty is a safe bet for a Romney campaign that wants to make the election a referendum on Obama.

"This year, the goal is a double-dip cone of vanilla," said Larry Sabato, an influential political scholar at the University of Virginia. "Romney is clearly vanilla, and you don't want to mix in a competing flavor. You're going to have a second scoop of vanilla."

Sabato's weekly Crystal Ball scorecard rates Pawlenty's prospects second only to those of U.S. Sen. Rob Portman of Ohio. Portman is seen as a conventional pick who gets the edge mainly because he could help put a critically important state in Romney's column.

Base politics

Few expect Pawlenty to deliver Minnesota. The state has produced two Democratic vice presidents in modern history and has not gone Republican in a presidential election since Richard Nixon won it in 1972. But as a former two-term GOP governor from a bluish state, Pawlenty is seen as an affable conservative who does not scare away the all-important swing voters.

That's the same calculation Pawlenty banked on in his own presidential campaign, which offered up bedrock conservative values in a mild-mannered, hockey-playing, Midwestern package. In the end, he was not the red-meat Republican the Tea Party base wanted.

Neither was Romney at the time. But now that the former Massachusetts governor is going up against Obama, his task is to hold the center more than shore up the right.

"Obama unites the Republican base," said Romney advisor Vin Weber, a Washington lobbyist and former Minnesota congressman.

Pawlenty has stirred the pot of media speculation since he fired up crowds for Romney at a rally on Saturday in Pennsylvania. But Weber says nobody truly knows Romney's leanings besides longtime confidant Beth Myers, who is leading the search for a running mate.

'Checks a lot of boxes'

Pawlenty, for his part, has shifted from saying he'd be happy to serve Romney in any capacity to saying he would be "honored" to serve as vice president.

Other contenders include Govs. Bobby Jindal of Louisiana, Nikki Haley of South Carolina and Scott Walker of Wisconsin, who gave the GOP a boost this month in an easy recall election victory. Also mentioned is Wisconsin U.S. Rep. Paul Ryan, author of the GOP's main budget blueprint to reduce the national debt.

But none of that competition has been immersed in the pressure chamber of presidential politics as much as Pawlenty.

"You really don't understand what it's like to run for president until you've actually done it," said veteran GOP strategist Eric Woolson, who was one of Pawlenty's top advisors in Iowa.

Pawlenty had a notably bad moment in one of the presidential debates when he appeared to back off of his criticism of Romney's Massachusetts health overhaul that he had previously dubbed "Obamneycare." But Woolson, who also worked on Vice President Joe Biden's 1988 presidential run, said Pawlenty has grown as a candidate since then and would hold up in a VP debate. "Tim Pawlenty measures up," he said.

In tough economic times, political analysts also see Pawlenty's blue-collar roots in South St. Paul as an ideal counterweight to the Romney image of wealth and privilege promoted by Democrats. Pawlenty's evangelical faith also could serve as a reassuring antidote to those with qualms about Romney's Mormonism.

"He checks a lot of boxes people would be looking for if the conventional wisdom is this race has shifted and it's very close," Golnik said. "He complements Romney's story."

Another consideration is chemistry. Whatever qualities Pawlenty brings in terms of leadership and experience, Weber said, "we know pretty well that the Romneys, at a personal level, really like the Pawlentys."

In the end, Pawlenty's chief virtue could be a lack of controversy, underscoring the political maxim that the main trick for the No. 2 spot is do no harm.

"With Pawlenty, what you get is a very respectable VP candidate who won't cause you problems and will pass the Oval Office test," Sabato said. "But he isn't going to make a great deal of difference in the campaign."

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.