01:36: The debate is officially one-third over. In the first segment, neither candidate has made any major gaffes or outstanding zings or wins against their opponent.

01:27: Romney brings up China, says he'll send programs to the state level and make cutbacks. He sites Obama's spending during the past four years.

Obama sites the bloated deficit as something he inherited due to two wars paid for on credit and other spending from the past administration.

Lehrer asks Romeny about the Simpson-Bowls plan. Romeny says he has his own plan. Romeny goes back to the idea that raising taxes kills businesses, and that many Americans are employed by the nation's largest businesses.

01:26: Leherer launches into the second segment in the six-segment debate. He asks each candidate how he will tackle the deficit.

01:21: The remaing 3 percent of businesses are where a large number of Americans are employed, Romeny counters, while giving another personal example of an American he has met in his experience in politics.

Obama starts crucnhing the numbers, stating that Romeny is attempting an impossible feat.

Romney repeats that he's not in favor of a $5 trillion tax cut. "That's not my plan,' he says, stating that his plan is not like anything that has been tried before.

01:19: Obama says 97 percent of businesses would not see their taxes go up under his plan. Obama says Romney's definition of small business includes large businesses.

The tax issue has become the first real sparring match of the debate.

01:15: Obama says Romeny would burden the middle class with top-down economics while middle class families are burdened further.

Romeny says everything that Obama has just said about his tax plan is inaccurate. He says he won't put in a tax cut that adds to the deficit. He also says he won't reduce the share payed by high-income individuals.

"I will not reduce the taxes paid by high-income Americans" Romney reiterates a second time.

01:08: Lehrer asks Obama to address Romney on trickle-down economics.

Obama says he agrees with Romeny on energy, but believes in energy sources of the future such as wind. Obama says Romeny's call for a $5 trillion tax cut among other expenses will not solve the economy's woes.

01:06: Romeny then greets the audience and congratulates Obama on his anniversary. Romey shares personal stories of Americans he's met on the campaign trail who he says need a new economic path. Then outlines a five-step path to a better economy that includes energy independence and a balanced budget.

01:04 GMT: FIRST QUESTION is on how each candidate plans to creat new jobs.

Obama makes the first response and begins by wishing his wife a happy anniversary. Then begins on an overview of the state of the economy.

01:01 GMT: Lehrer asks for a silence audience -- don't expect any boos or cheers.

Obama and Romey walk on stage, shake hands, greet the audience with a wave and take to their podiums.

01:01: Lehrer welcomes the audience to the first of the 2012 presidential debates.

00:58 GMT: Going into tonight's debate, a new Wall Street Journal/NBC News poll has given Obama a lead among likely voters of 49-46 percent, consistent with a RealClearPolitics poll average showing Obama up by 3.5 percentage points. A National Public Radio poll today showed Obama leading 51-44 among likely voters nationwide and 50-44 in battleground states, while a Washington Post-ABC News poll gave Obama a larger 52-41 lead in swing states.

00:54: PROXY WARS: Each of the candidates has been prepping for tonight with a proxy debate partner tasked with impersonating the mannerisms and ideology of their opponent. Republican Senator Rob Portman of Ohio stood in for Obama during mock debates with Romney over the past month. Having played Obama, John Edwards, John Kerry, Joe Lieberman and Al Gore in previous mock debates, Portman is something of an expert Democrat. Democrat Massachusetts Senator John Kerry, who is a seasoned veteran of presidential debates having run for office in 2004, has been playing Romney for the Obama camp.

00:52: Ann Romeny is wearing a prim white skirt suit with pearls while Michelle Obama is wearing a purple jacket with a multi-colored blouse underneath.

00:49: Michelle Obama and Ann Romney greet each other in the audience with a polite embrace and kiss.

00:48 GMT: What does a presidential candidate do in the minutes leading up to his first ever presidential debate? Per photos from the wire stills, who were allowed into Romney's hold room, Romney and his sons were engaged in a pre-debate game of Jenga.

00:45 GMT: Apart from the debate, today is a landmark day for Obama as it's his 20th wedding anniversary to his wife Michelle.

"I told Barack, 'This, you know, attending a presidential debate on my 20th anniversary is probably the worst way for me to spend (it).' ... I get so nervous at these debates," she told CNN.

00:40 GMT: THE GUESSING GAME: Twenty minutes out from the debate, each candidate's performance remains a giant unknown. In a Gallup Poll released this morning, however, 57 percent of Americans said they think Obama will do a better job than Mitt Romney, while 33 percent believed the reverse ? that Romney will do better than Obama.

00:34 GMT: Both Obama and Romney have arrived at Ritchie Center, the venue for tonight's debate and home to the University of Denver's hockey team.