WASHINGTON -- Mitt Romney listens. Newt Gingrich lectures.
Gingrich wants to colonize the moon. Romney vows he'd fire anyone who came to him with such a harebrained idea.
Romney is appreciated for clear-eyed analysis, Gingrich for dreaming big.
Gingrich is knocked for being a blowhard, Romney for drifting with the political winds.
Romney tries to humanize himself, with sometimes cheesy results.
Gingrich is all too human; just ask his wives.
By now it's clear that the Republican nomination contest is showing the nation stylistic extremes rarely seen in modern presidential politics. Put simply, the race, at the top, is between a madcap professor who most appreciates the flow of ideas when it comes from himself and a buttoned-down CEO who likes to fire up a PowerPoint presentation and sound out everyone in a room.
If past is prologue, here is how Romney and Gingrich presidencies might look:
"I'm a business guy," Romney likes to say. He's not just talking about his policies.
President Mitt Romney would wield charts and graphs, and study problems from every angle.
Beth Myers, his chief of staff when he was Massachusetts governor, remembers when a group came to Romney with the consensus answer to a problem.
"Who's going to present the other side?" Romney wanted to know.
He promises "sobriety, care, stability."
"I'm not a bomb-thrower, rhetorically or literally," he said recently.
Soon after Romney became governor, his Harvard Business School credentials and penchant for PowerPoint clashed with the commonwealth's old school culture of glad-handing.
Veteran lawmakers complained about lack of access to Romney, a perception that wasn't helped by his decision to commandeer one of the Statehouse elevators, barring the public, lawmakers and reporters from using it during his four-year term. The elevator became a symbol of his aloofness. (It was reopened to the public after he left.)
Romney's efforts at control went beyond that.
He routinely used velvet ropes to mark out his travels around the Statehouse and prevent citizens from walking into the outer reception area of the governor's office.
On the other hand, he met legislative leaders of both parties every Monday, rotating the location among all their offices. He pledges similar outreach to lawmakers in Washington if he becomes president.
Judging from his past in business, as governor and as chief of the Salt Lake City Olympics, there won't be much schmoozing when a President Romney comes calling on Capitol Hill.
"We wouldn't have a half-hour meeting with 15 minutes of social talk," said Thomas Trimarco, Romney's secretary of administration and finance during his last 18 months as governor. "He wants information. He wants data. That's how his mind works. That how he makes decisions."
Cindy Gillespie worked with Romney for nine years, at the games and as an aide in the governor's office. She said: "There's no point in being a `yes' person with Mitt. It wouldn't get you anywhere."
But Kenneth Bullock, who was on the Olympic board, said Romney was overly controlling and tried to grab all the glory. "If you listen to him, he created the vision, he orchestrated it, and he saved it."
That's hardly a shocking trait in Washington, a beehive of fungible credit-taking. In fact, it's downright presidential.
But if Romney has nailed the qualities of discipline and self-promotion expected of a president, he's still got work to do on what comes out of his mouth.
His comment that "I'm not concerned about the very poor" because they have a safety net was just the latest groaner from a man of riches who tends to stumble when trying to show a common touch.
And throughout the primary campaign, he's struggled at times to loosen up.
Take his visit to Mary Ann's Diner in Concord, N.H., in the summer.
As Romney posed with several waitresses in front of a jukebox, he urged them to squeeze in closer and then pretended one of them had goosed his behind.
"Oh my goodness!" he exclaimed.
That's about as racy as you're going to get from Romney, a Mormon who says the "enduring truths" in his life are his wife, his five sons and his 16 grandchildren.
Out with teleprompters. In with Lean Six Sigma.
Oh, and hang on to your hat.
If elected, Gingrich would barrel into the White House with a forklift full of ideas.
Don't expect him to tiptoe around sore spots or proceed cautiously.
The candidate who pronounces himself "much more effective per hour" than he was in his 40s promises to roll out "extraordinarily radical" ideas to change American culture.
"He must exhaust his staff," says the Rev. Al Sharpton, who got to know Gingrich when the two traveled the country together in 2009 to promote education reforms as a right-left tag team. "He's got 50 different ideas every hour and 50 different analyses and 100 historic anecdotes."
After mocking President Barack Obama for his heavy reliance on teleprompters, Gingrich is sure to avoid the device whenever possible. But don't expect Gingrich to run out of things to say.
Republicans who worked with Gingrich on Capitol Hill when he was House speaker recall meetings where they all could do was nod their heads while the former college professor held forth for hours on Greek history, "Future Shock" and whatever else was on his fevered mind.
Gingrich already has announced plans to teach an online course as president to keep people up to date on what he's up to – free of charge, he hastens to add.
"He would certainly be an activist president," predicts former Rep. Mickey Edwards, R-Okla., who says Gingrich as House speaker concentrated power in his own hands. "He would not be accused of being too above the fray. He'd be more like LBJ in the sense of `I'm the boss.'"
Bob Dole, who was Gingrich's counterpart in the Senate and the 1996 GOP presidential candidate, offered a scathing critique of the speaker before the Florida primary, when party insiders decided Gingrich was becoming too threatening to Romney's prospects and needed his wings clipped. "He was a one-man band who rarely took advice," Dole commented. "It was his way or the highway."
As for those ideas Sharpton talked about, Dole cuttingly said "most of them were off the wall."
Presidents arrive with their own personal likes and dislikes. Expect an emphasis on animals in a Gingrich presidency.
He's been fascinated with them ever since he painted stripes on his leather jacket as a kid to look like a zebra. And expect to hear a lot about Lean Six Sigma, a managerial philosophy designed to promote efficiency that Gingrich says could save the federal government billions.
For all of his conservative bombast and promises of radical change, Gingrich is not immune to compromise and bowing to public sentiment.
Even Ronald Reagan knew to settle for 80 percent of what he wanted, Gingrich says.
"You can't have a hard-right presidency succeed," he said at one point. "There's not a right-wing majority in this country."
Gingrich also promises to rein himself in as president, saying the chief executive must be more disciplined than an analyst who can say anything.
"The person to whom you're entrusting the leadership of the United States had better think long and hard before they say things," he said early in his candidacy. "I think that's a fair criticism of me."
Associated Press writers Sharon Cohen in Chicago and Steve LeBlanc in Boston contributed to this report.