By BEN FELLER
AP White House Correspondent
RICHMOND, Va. (AP) — Deep in the longest day of his campaign, President Barack Obama was in a Las Vegas casino, gambling that his re-election bid needed one more stop. It was 1:40 a.m. on his clock, and he was pleading with the hotel cooks and waiters for their votes.
"I need you so that I can keep on working for you," he told workers at the Bellagio. His voice was going. And soon, he was going again, too.
Obama's 40-hour blitz across America on Wednesday and Thursday was a sign of how the final campaign of his life will look and feel through Nov. 6. His presidency in doubt, Obama is not just chasing votes. He is chasing time.
The soaring importance of the early voting — happening now in key states such as Ohio, Nevada, Colorado, Iowa and Florida — means the president is into the last-minute sprint, with 12 days to go.
"The old model is gone," said adviser David Plouffe, standing in the early darkness in Tampa, Fla., after Air Force One's red-eye flight from Vegas. "Every day is Election Day now."
Obama cast his ballot early today , returning to his hometown of Chicago to drum up support for early voting. He signed forms and showed his driver's license at a South Side Chicago voting site and then voted at a blue voting machine.
The president said, "all across the country we're seeing a lot of early voting." He says it was "really convenient" but jokes, "I can't tell you who I voted for."
It was the first time a sitting presidential nominee voted early and reflects the Obama campaign's strategy to encourage as many voters as possible to vote early or by absentee ballot.
About 35 percent of the electorate is expected to vote before Election Day.
Even by campaign standards, where the travel days at this stage are supposed to be full of energy and urgency, Obama's trip covered remarkable ground. More than 7,600 miles of it.
And often it has come with Obama boasts about his pace.
"Our 48-hour, marathon-extravaganza fly-around. We are pulling an all-nighter," he said from Denver. "No sleep. Quite a bit of coffee."
Actually, Obama doesn't drink coffee. And he ends up sleeping a little in his bed on the plane. But the all-nighter part sure felt right, the way Obama and his entourage blurred through five time zones to maximize campaign time.
Obama ricocheted from the heartland to Hollywood, from the mountains to the desert, from ocean to ocean. He ate pizza in Iowa, laughed with Jay Leno in California and mocked Mitt Romney into the wee hours of the Nevada night.
"Vote! Vote! Vote!" the president shouted by then, his message shrunk to its essentials.
Along the way, a helicopter for the press broke down. A van carrying his staff wouldn't start. Air Force One hit monster turbulence. But that was just a memory by the time Obama had a spectacular sunset helicopter ride over Los Angeles, or when he saw 15,000 people waiting for him in the Virginia sun.
The itinerary centered on six toss-up states: Iowa, Colorado, Nevada, Florida, Virginia, and Ohio. He included California to appear on "The Tonight Show," and Illinois so that he could make a splash of voting early as president.
Obama's campaign day lasted more than 18 hours on Wednesday, technically ending at about 2:30 a.m. EDT. His friends and advisers competed for floor space on the plane to sleep. That didn't last long. Obama was in Florida and campaigning anew by 7 a.m. EDT.
That's when signs of punchiness started to show. Some of Obama's aides broke into dance when a familiar Stevie Wonder song played at the end of his Tampa event. The president sounded hoarse.
"I'm just going to keep on keeping on," he said.
Soily Rivera, a 28-year-old homemaker from Tampa, brought her 6-month-old son Jose Santa Maria to hear Obama. When asked if Obama's marathon trip to the battleground states could show desperation, she shook her head in disagreement.
"No, determination," she said. "Determination. Big time."
That is what Obama's campaign wants voters to see — a president full of drive and vigor. Yet Obama also has to campaign this hard because he is fighting for survival. Polls show a remarkably close race in all the key states.
He used spare time for political advantage. In separate conference calls aboard Air Force One, Obama spoke to 17,000 campaign volunteers, 9,000 undecided voters and 50 disc jockeys from swing states.
On the ground, Obama kissed babies, took photos with his motorcade drivers and bought doughnuts for firefighters. He joked with one young boy in Aurora, Colo., that he had the same big ears as the president.
"He enjoys days like this," campaign spokeswoman Jen Psaki said during one of Thursday's flights, somewhere over the hills on the way to Virginia. "They're busy. They're hectic. We'll sleep on Nov. 7th."
If Obama accomplished any single goal, it was to educate people that many of them can vote right now, so they don't have to get entangled with work or child-care problems on Election Day.
Back in Denver, Sarah Romero, 51, has gotten off her day job at 2 p.m. for the past two months and headed over to her local Obama campaign office to volunteer for the president through the evening.
She was happy Obama was swinging by Denver. But not blown away by his pace. That's his job.
Said Romero: "They get naps on the plane."
Associated Press writers Nicholas Riccardi in Denver and Tamara Lush in Tampa, Fla., contributed to this report.