WASHINGTON - When Mitt Romney's wife, Ann, was diagnosed with breast cancer in late 2008, one of the people who reached out to the couple was newly elected President Barack Obama.

It was one of the few personal interactions between Obama and Romney.

"He was kind enough to call our home when my wife was ill, and he said that he and Michelle had my wife in their prayers," Romney said in an interview after the call. "I said, 'Mr. President-elect, Ann and I have you in our prayers'. And we do."

Even as their political fates have become more entwined, Obama and Romney have had little opportunity to connect directly. In fact, when the Democratic president and the former Republican governor of Massachusetts stand alongside each other during Wednesday night's presidential debate in Denver, it will be their first face-to-face meeting in nearly five years.

"I don't really know him well," Obama said in an interview with The Associated Press. "I think Gov. Romney obviously has achieved extraordinary success with his businesses, and he's obviously very focused on achieving the presidency. He cares deeply about his family, and I think he cares deeply about his faith."

Romney has had similarly kind words about the president as a father and family man. But most of their descriptions of each other during the campaign are far less complimentary, and that probably will be the case in the debate.

Romney accuses the president of having "more European than American" views. Obama says Romney has written off half the country.

The two do have a few similarities. They're both graduates of Harvard Law School; Romney also has a business degree from the Ivy League university. Each is a multimillionaire, though Romney's estimated $250 million fortune far exceeds Obama's net worth, which is as much as $8.3 million.

When people get one of their first looks at the rivals standing side by side Wednesday, they'll see a Republican who is 14 years older and an inch taller than the 51-year-old president, who stands 6-feet-1.

Obama and Romney first met in 2004 at a gathering of Washington's political and media elite. Romney, then governor, and Obama, a senator-elect from Illinois, were picked by the Gridiron Club to deliver speeches at the group's dinner. The private event's festive atmosphere, however, meant their dueling speeches were more about cracking jokes than outlining their policy differences.

By the time their paths crossed again, the rising political stars were presidential contenders. Seeking to line up votes in the New Hampshire primary, they both showed up for the 2007 Labor Day parade in the town of Milford. They shook hands, exchanged a few pleasantries and turned their attention to the voters.

New Hampshire was also the site of what aides to both men believe was their last face-to-face meeting before Wednesday's debate.

In January 2008, the Republican and Democratic primary candidates were holding back-to-back debates in Manchester. After the Republicans wrapped up, the moderator invited the Democrats waiting in the wings to join them briefly onstage for a brief show of bipartisanship.

Obama and Romney found each other in the scrum. They smiled and shook hands, with Obama placing his hand warmly on Romney's arm.

Obama went on to win the White House. Romney dropped out of the Republican race shortly thereafter.

They've had one direct exchange during the 2012 campaign. Obama called Romney in late May after the Republican clinched the GOP nomination. He congratulated Romney and told him he "looked forward to an important and healthy debate about America's future."

Aides to both men described the call as brief and cordial.

Their scant personal relationship is in many ways the result of potential pathways to the presidency that had little to do with Washington. Obama spent just two years in the Senate before launching his 2008 White House bid. Romney spent most of his career in the private sector and has never worked in the nation's capital.

It's a marked contrast to many of the other political pairs that have faced off against each other for the presidency. Obama and his 2008 GOP rival John McCain, for example, had worked together in the Senate before facing each other in the general election.

Similarly, President George W. Bush and his 2004 Democratic challenger, Sen. John Kerry of Massachusetts, knew each other from work in Washington. Same with President Bill Clinton and then-Kansas Sen. Bob Dole, the Republican nominee in 1996.

Sara Taylor Fagen, who served as a political adviser to Bush, said Obama and Romney's lack of a personal relationship would likely be a mixed blessing on the debate stage.

"On the one hand, you've depersonalized it. You can say, 'I don't really know you, I'm totally comfortable saying whatever I have to," Fagen said. "On the other hand, familiarity is a really helpful thing. Even though you may be fierce opponents, it also gives you a comfort level."

Though one is president and the other wants to be,

Obama and Romney are rivals with little personal history