DENVER, Oct. 8, 2012 -- They form what is perhaps the smallest and least influential voting bloc in the 2012 presidential race. But this campaign season, the nation's oldest voters -- 100 years, plus -- are proving that they may have the most grit, and an affinity for President Obama.

Braving sweltering summertime heat, massive crowds and bitter partisanship, American centenarians with a resilient political spirit have been joining election-year rallies across the country, often despite the physical fragility that comes with great age.

"I'm 101 years old! 101 years old!" yelled one man at an Obama town hall meeting in Cincinnati in July, triggering a shouting match of ages.

"105!" screamed a woman in the back of the room, motioning to an older woman seated in a wheelchair.

Obama, who had just taken the stage, looked incredulous. "OK, you guys -- 105 right here!" he said, pointing to the woman. "105! God bless you. 106 next month. She's beautiful."

Spotted at rallies from Jacksonville, Fla., to Las Vegas, Nev., and states in between, politically-active centenarians form a select group from among the roughly 53,000 Americans at 100 years-old or older, according to the U.S. Census Bureau. Experts say they have predominantly left-leaning views that reflect the influence of Depression-era values on their political coming-of-age.

Ruth Wench, a retired school teacher and the oldest woman in Osawatomie, Kan., at 102, was two years-old when Republican President Teddy Roosevelt visited her town. She told ABC News at an Obama rally in March that she hadn't seen a president in the flesh in the hundred years since.

"It was very important and exciting to me of course to see one alive," Wench said, explaining her trip from a local nursing home to the high school in a wheel chair. "I've seen pictures and TV of course, but to see one who has much interest in middle class people in little Osawatomie. That God impressed on him to come to Osawatomie and encourage us --"

Clutching a copy of Obama's book "Dreams of My Father," wrapped in a plastic hair net, Wench said she hasn't always been a Democrat but hopes to vote for Obama in November because, she said, he embodies Franklin Delano Roosevelt's New Deal ethic. "If I'm still alive, I will," she said of the desire to vote.

Polls show Republican presidential nominee Mitt Romney maintains majority support among voters 65 and older -- a group that Obama lost handily four years ago. But the president may hold an edge among voters in the upper echelon of that demographic.

"Anybody here over 100 years old?" Romney asked a crowd of seniors at a New Hampshire town hall meeting late last year. No one replied. "Not yet, but we're getting there, right?" he added, encouraging the crowd. "We're on our way."

No precise polling data exists on the politics of America's oldest voters . But long-term generational data from the Pew Research Center, coupled with more than a dozen anecdotal interviews with voters around the 100-year mark, suggest the sub-group remains more left-leaning than their slightly younger peers on the 2012 race.

"One way to look at the political leanings of generations is to sort people by the political environment when they became politically engaged," says Pew in a report "The Generation Gap and the 2012 Election."

"For example, not so long ago, voters 65 and older were predominantly members of the Greatest Generation, most of whom came of age during FDR's presidency and were fairly reliable Democrats, even into their later years," Pew found. "As recently as 2004, members of the Greatest generation supported [Sen.] John Kerry by a greater margin than did all voters in that election."

Wilma Turney, a 92-year-old member of the Greatest generation from Denver, Colo., says she is a Democrat today because of what FDR did for the country more than 70 years ago.

"I've seen a lot of presidents. This is my last; this will be my last one," Turney told ABC News in July as her daughter wheeled her into the Auraria Event Center in Denver to see President Obama.

"I hear him for what he is, for the people that I grew from and the Great Depression that nobody else around here saw," she said of Obama. "I believe in loving each person for who they were and what they lived for, and think he does, too."

Stepping Into Political Spotlight

The exclusivity of the centenarian class has made its members' involvement in the 2012 presidential race among the noteworthy moments of the campaign.

The Obama campaign has begun promoting the support it has from centenarian voters, using a new web video to highlight the story of one 106-year-old voter – Margaret Harris of Springfield, Ky.

Behind the scenes, the president has even been known to solicit a little advice from his most senior campaign fans.

Wilbur and Theresa Faiss of Las Vegas, one of the longest-wed couples in America at 79 years, waited on line for hours to see the president at a Nevada event in March. "You gotta tell me your secret for staying married for 79 years," Obama said upon greeting Wilbur Faiss, 100.

"You should know what it is," Faiss quipped back, with wife Theresa, 96, by his side.

"Just do what she tells you to do?" Obama asked.

"No," said Faiss sternly. "Compromise!"

Shifting Political Allegiances

Pew forecasts that a dominant Democratic inclination among today's oldest voters will likely give way to a more right-leaning outlook over the next few years with rise of a new generation that came of age politically during Republican presidencies.

These members of the so-called Silent Generation, informed by the politics and policies of Harry Truman and Dwight Eisenhower, are already showing a tendency to vote more Republican than average, too, Pew says. For now, however, it's the legacy of Franklin Delano Roosevelt that underpins the allegiances of many in the 100-year-old-plus group.