And, in between, he'll try to bring back a little of the Obama magic from years past that attracted a new generation of voters and re-energized Democratic diehards.
That's what Sheryl Ginsberg, a first-time delegate from Salt Lake City, wants to experience from her seat inside Bank of America Stadium on Thursday. She simply wishes to be inspired.
"I want him to bring back that feeling from when he first spoke about the need to come together," she said. "I want to hear that and be touched by that again. The differences we have are beautiful, and they make us better."
In 2004, Obama was a three-term state senator from Illinois and a candidate for the U.S. Senate. He seemed a shoo-in to win that November because his Republican opponent withdrew after allegations surfaced that he frequented sex clubs.
Democratic presidential candidate John Kerry and his campaign asked the little-known Obama to give the keynote address on the second night of the convention in Boston. In less than 20 minutes, Obama outlined his background, lauded Kerry's accomplishments and called for a unified America.
"There is not a liberal America and a conservative America there is the United States of America," he said in a fervent cadence that rose above the cheers of the crowd. He dismissed the blue-and-red-state shorthand for those areas that support Democrats and Republicans.
"We worship an awesome God in the blue states, and we don't like federal agents poking around in our libraries in the red states," he said. "We coach Little League in the blue states and, yes, we've got some gay friends in the red states."
He was an instant hit and a sudden, unexpected national figure within the Democratic Party.
Phenomenon • "I said, 'Oh my God, he's going to be the first black president.' I just knew it," said Ginsberg, a retired social worker, who watched the speech from the basement of her Salt Lake City home.
Joe Hatch, the Democratic national committeeman from Utah, was there in Boston and has watched every convention since 1968.
"It was instantaneous just how great it was," he said. "I've never seen anything like that."
Gail Turpin, another first-time delegate from Utah, said: "I haven't felt that enthusiastic about a politician, probably since Bobby Kennedy."
Among the people Obama brought to their feet was Hillary Clinton, whom he would face and ultimately beat in a back-and-forth 2008 Democratic primary season, which, while contentious at times, was imbued with a sense of history in the making. Either the first black man or the first woman was going to represent a major political party for president and whoever emerged had a better-than-average chance of winning the White House.
His 2004 address helped Obama make inroads with the party, but Clinton was already Democratic royalty and was widely seen as the front-runner in the race to replace two-term President George W. Bush. What Clinton didn't have was Obama's outsider appeal and dynamic personal narrative: His mother was a white woman from Kansas, and his father, whom he barely knew, was a black man from Kenya. He received an Ivy League education but spent his post-college years as a community organizer in poor areas of Chicago.
His crowds grew larger, buoyed by young voters, and eventually he wrapped up enough primary wins to claim the nomination.
Obama's 2008 acceptance speech also included lofty prose and even a few lines nearly identical to his 2004 address, but this time he delivered them in a stern, serious tone. He wanted to empathize with those impacted by the economic collapse and appear presidential and in command.
Post-partisan • Emerging from between faux-Greek columns, Obama hammered Bush but also urged a football stadium full of people in Denver and millions watching at home to look past the standard partisan divides, promising to reinvent Washington politics.
"What has also been lost is our sense of common purpose our sense of higher purpose. And that's what we have to restore," he said, before pre-emptively brushing off critics who were certain to discredit his motives. "That's to be expected. Because if you don't have any fresh ideas, then you use stale tactics to scare the voters. If you don't have a record to run on, then you paint your opponent as someone people should run from. You make a big election about small things."
Fast-forward four years and Republicans are now alleging Obama is trying to turn this election into a debate about small things to distract from his record, arguing that the debate about the release of Romney's tax returns and attack ads claiming the GOP nominee is out of touch with regular Americans are attempts to divert attention from anemic economic growth, high unemployment and a rising national debt.
"His campaign is not about the future, it is trying to define Mitt Romney as a bad choice for voters come this November because the changes the president promised never came true," said Ron Bonjean, a Republican strategist who has worked for congressional leaders. "The vision he presented to the country hasn't worked, so the only thing left is to attack and destroy your opponent and hope that voters will keep the devil they know in office, rather than the devil they don't."
Former Sen. Bob Bennett, R-Utah, said Obama faces a convention road loaded with land mines. A full assault on Romney will only feed voter cynicism and may turn off people. Soaring rhetoric may seem like a repeat of years past. And he won't be able to easily say the country is on the right track.
"He's on the defensive," Bennett said. "The shine is off."
Fighting back • But Utah delegates say Obama should use his convention speech Thursday to fight back against Republican claims and to contrast his vision with that of Romney. At the same time, they don't want him to shy away from his accomplishments during a trying time for the nation.
"We were confronted and handed the worst economy in 50 years," said Hatch, the Democratic committeeman from Utah. "We stopped the erosion. We did a lot of good things, and we are slowly building a foundation for an incredible future."
Delegates tout Obama's health care law as a major step forward and the bailout of the auto companies as a move that saved an industry and thousands of jobs. They note the passage of a law making it easier for women to sue for pay discrimination and the elimination of the military policy requiring gay service members to keep their sexuality a secret or face expulsion.
"What I expect is a recommitment to the unfinished work. There are a lot of issues that we still need to put our best minds to," said Karen McCoy, a delegate from Salt Lake City and a retired Veterans Affairs employee, who pointed to the pressing concerns of immigration, health care and the nation's financial well-being.
McCoy says Obama has struggled "with the harsh political realities of the Beltway" but that his vision for the government is one that trumps Romney's. She believed in the vision Obama shared in his first convention address in 2004. Unlike the Republican Party's goal of limiting the size, scope and power of government, she sees federal institutions as a way to help the needy and less fortunate.
She can recall a line that Obama used in 2004, repeated in 2008 and one he may well say again on Thursday: "It is that fundamental belief I am my brother's keeper, I am my sister's keeper that makes this country work."
The Democratic lineup
The list of key speeches during the three-day convention.
Tuesday • First lady Michelle Obama and San Antonio Mayor Julian Castro, keynote speaker
Wednesday • Former President Bill Clinton and Massachusetts Senate candidate Elizabeth Warren
Thursday • President Barack Obama and Vice President Joe Biden