WASHINGTON — In one corner, at 6-foot-2, with the bulbous nose, the silver hair, the global resume and the I-feel-your-pain grin: former President Bill Clinton.
In the other, at 5-foot-11, as formidable and corporate as Hillary Clinton was in 1992 but more content and with a style and take on motherhood that's Clair Huxtable-meets-Jackie Kennedy: Michelle Obama.
With the contest between Hillary Clinton and Barack Obama for the Democratic presidential nomination threatening to drag on past Super Tuesday on Feb. 5, voters outside Iowa, New Hampshire, Nevada and South Carolina may get to see how these unconventional candidate-spouses operate.
Bill Clinton needs no introduction, but Michelle Obama remains an unknown to many Americans, especially in the West.
"I'm embarrassed to say I don't know as much about her," said Jon Krosnick, a Stanford University professor who specializes in political psychology and has been observing how the Clintons campaign together.
Bill Clinton and Michelle Obama are far more involved, at least publicly, than are the wives of the two Republican front-runners, John McCain and Mitt Romney. Each is putting in heavy rotations on the surrogate campaign trail, although Obama still tries to be home evenings and weekends with the couple's two young daughters.
Both spouses have mostly been assets for their respective campaigns, but if the lead-up to the Jan. 26 South Carolina primary was any indication, Mrs. Obama and Mr. Clinton may yet draw blood.
Months ago, Obama made what some read as a personal dig at Hillary Clinton, saying, "If you can't run your own house, you can't run the White House." Then, when Clinton stepped up his attacks on behalf of his wife and tried to put Barack Obama in the Jesse Jackson-black candidate box, Obama charged before the TV cameras to say that, "When power is confronted with real change, it will say anything."
So far, Clinton has taken more media criticism — for his attempt to suggest that he never supported the Iraq war, for hogging so much of the spotlight that Barack Obama wondered aloud whom he was running against and for playing racial politics to limit the damage of his wife's landslide loss in South Carolina, the first Southern state to vote.
Obama has gotten an easier ride. Her connection with black women may have helped turn out voters who once had been torn between her husband and Hillary Clinton. But some of Obama's edgier comments could have exploded into controversy if she'd rolled them out before different audiences, say, during a general election campaign aimed at attracting swing voters.
Hillary Clinton was asked about her husband's role at the Thursday night Democratic debate in California.
"He (Obama) has a spouse, too," she replied.
"Thankfully Michelle is not on stage," Barack Obama interjected. "I'm sure she could tell some stories as well."
Clinton summed it up: "Well, one thing I think is fair to say: Both Barack and I have very passionate spouses..."
"We do, no doubt," Obama said.
"...who promote and defend us at every turn. .... But the fact is that I'm running for president, and this is my campaign," Clinton declared, to applause.
Michelle Obama's frustration at the personal and career sacrifices she's making for her husband is palpable, even though she says she's willing to give up something for the opportunity to leave a mark on history. And her calculation to put her husband in his place at times, talking publicly about his sloppiness or how their daughters find him too stinky in the morning, isn't something you'd expect from, say, Lady Bird Johnson or Laura Bush.
Krosnick said that Bill Clinton and Obama reflect "an increasing trend toward spouses being involved in campaigns. I think it's a reflection of the women's movement. Women are running major corporations now. It's something that is just a fact of life, so the idea that smart effective politicians would be married to smart, effective professionals who don't just sit quietly at home, that's going to be normal."
Both trained as lawyers, Clinton and Obama are verbally adept, with the ability to scathe, uplift or empathize on and off-script.
But either spouse could become a liability, Krosnick said, especially in the general election — Clinton because of how much Republicans revile him and Obama because she's unpredictable and doesn't have much experience in the national spotlight.
"As this thing goes on, every single word becomes vital," Krosnick said.
Carl Sferrazza Anthony, a biographer of first ladies and historian for the National First Ladies' Library in Canton, Ohio, said that Clinton and Obama both are "pivotal" figures in their spouses' campaigns.
But he sees them as fundamentally different.
Anthony considers Obama a grounding force for her husband. Growing up in a working-class black Chicago neighborhood, her experience as an African-American is more typical than Barack Obama's biracial childhood in Hawaii and Indonesia. Her ascendancy to Harvard Law School and the business world, as a hospital executive, arguably is more hard-won.
While her biography may be atypical for a candidate's spouse, her style on the trail isn't unprecedented. Anthony sees strains of Florence Harding, who brought her experiences as a divorcee and businesswoman to the trail in advocating her husband's understanding of women's challenges in 1920. Anthony also sees strains of Jackie Kennedy and Hillary Clinton in Obama.
Clinton's experience as a past president and his political acumen are unprecedented in a candidate's spouse, Anthony said. In contrast, he said, Obama seems interested in public policy, but "I don't think she has a natural instinctive interest in the art of politics at all. I don't think she has been politically ambitious."
A Pew poll last October found that Clinton's presence could cut both ways in his wife's campaign. Asked whether his influence on a Hillary Clinton presidency would be a positive or a negative, most people considered him a plus, 64 percent to 19 percent. But asked whether they liked the idea of Clinton being back in the White House, Americans had a more divided reaction, with 45 percent saying they liked the idea and 33 percent disliking it.
How would America receive a first lady Michelle Obama? Pollsters say they don't know. Neither national polling groups nor Illinois organizations have been asking, and Obama's own aides say they're not aware of any data on her favorability.
After Super Tuesday, however, if Barack Obama's ahead, you can be sure such polls will emerge.