WASHINGTON — When he steps off of Air Force One in sunny Hawaii to begin his annual Christmas vacation, President Barack Obama will have managed to escape Washington, but not "the bubble."

At home or on the road, the president lives in an isolating world — a White House world staffed by thousands of people who protect, advise and serve him at an annual cost to taxpayers of about $1.5 billion.

He lives, works and plays behind fences and a wall of Secret Service agents. He never cuts the grass, does the laundry, or cleans the kitchen. He’s driven a car only twice in nearly four years, once for 10 feet. He rarely goes to church; a chaplain visits him at his private Camp David mountain retreat. He doesn’t go to movies; first-run releases are sent to him.

He says he tries to break through, reaching out for contact with ordinary Americans and the occasional feel of real life. But as Obama himself admits, it’s hard.

"There is an inherent danger in being in the White House and being in the bubble," he said recently when asked following big midterm election losses if he’d lost touch with the American people. "When you’re in this place, it is hard not to seem removed."

In the distant past, people could walk up to the White House and talk to the president. Then people started shooting at presidents, and the fences went up.

Once, they could drive by the White House. Then someone used a truck bomb to blow up a federal building in Oklahoma City, and the Secret Service closed that part of Pennsylvania Avenue to traffic in 1995.

Once, President Harry Truman could take walks around the streets of the capital. Then assassins tried to kill him, and presidents retreated behind the fences. When Obama walked a few hundred feet across Pennsylvania Avenue in mid-December to meet with business leaders at the nearby Blair House, one of his heavily armored limousines stood by and pedestrians were barred for blocks around.

Indeed, the wall separating the president from the people has grown ever higher, the bubble ever larger, particularly with the threat of terrorism.

Where President George H.W. Bush could sneak out for a quiet dinner at a Chinese restaurant, Obama has to plan well ahead to leave the building, even when he’s taking what looks like a spontaneous outing for a hamburger.

"The ability to move any president is not what it was in 1989 or 1991," said White House press secretary Robert Gibbs. "We couldn’t decide to go somewhere tomorrow. It just takes a long time to get that apparatus moving."

Security is one way a president is cut off from people. Lifestyle can be another. The way presidents live can reinforce their connection with the American people or punctuate the differences.

"They’re all in a bubble," said presidential historian Bert Rockman.

"Some of them have a more common touch than others. Clinton certainly did. Reagan did. The younger Bush did for a while. Others have lacked the common touch. Nixon didn’t have it. Carter didn’t have it. Obama is very comfortable in the company of intellectuals."

Truman not only took walks, he also insisted on washing his own socks and underwear. Ronald Reagan cleared brush and rode horses on his ranch. Bill Clinton had a taste for McDonald’s. George W. Bush drove his own pickup truck at his ranch.

Obama doesn’t do any of that.

At the White House, he has a staff of about 100 to cook and clean for him.

At the Camp David retreat in Maryland’s Catoctin Mountains, the Navy provides staff to take care of the 49 buildings. It boasts a four-bedroom presidential lodge, a heated swimming pool, stables, a sauna, a movie theater, tennis courts and a golf driving range. "It’s about the only place you can really walk freely and be alone virtually unencumbered," Reagan told Clinton after his election.

Obama went to Camp David 10 times his first year in office, less frequently than some predecessors. George W. Bush cherished the seclusion, going an average of 18 times a year.

All told, nearly 6,600 people work to take care of the president, according to Bradley H. Patterson, a veteran of the Eisenhower, Nixon and Ford White Houses who’s written extensively about White House staff.

That includes the Secret Service, the White House policy staff, the people who take care of the White House and its grounds, as well as Camp David, Air Force One, the Marine One helicopters and the armored cars. It also includes a staff florist and calligrapher.

The price tag totaled $1.5 billion in 2008, the latest year records are available. The cost is all but hidden in the federal budget, spread out in 12 different places, Patterson said, including the departments of Defense and Homeland Security. The 200 to 300 people who clean and maintain the White House are listed in the General Services Administration and the National Parks Service, for example.

"There’s no one White House budget," Patterson said.

Beyond the extraordinary services offered to him, a president makes personal choices about how much to connect to life outside his enclosed world.

"One of the challenges that we’ve got to think about is how do I meet my responsibilities here in the White House," Obama said last month, "but still have that opportunity to engage with the American people on a day-to-day basis … give them confidence that I’m listening to them."

He doesn’t attend church often and thus seldom mixes with other congregants.

A movie buff, he doesn’t go to theaters or wait in line with other people for popcorn. Instead, the Motion Picture Association of America sends him movies. Obama has a private theater on the ground floor of the White House, and aides said he also watches them on his laptop.

Secret Service agents have chauffeured him since soon after he became a presidential candidate, so he’s only driven twice since 2007. He steered a new Chevy Volt all of 10 feet during a factory visit in July, and once took an unseen drive of a Dodge Charger during a visit to the Secret Service training facility.

When he does interact with people in Washington, it’s often with elites.

He attends events at his daughters’ exclusive Sidwell Friends School, a favorite of the city’s political and media elite. He meets frequently with journalists from The New York Times, giving them access to his office and senior staff while refusing to talk to most media based outside the New York-to-Washington corridor.

He keeps in contact with a small group of close friends, including Chicago pals Martin Nesbitt, who owns a chain of airport parking lots, and Eric Whitaker, the executive vice president of the University of Chicago’s Medical Center. In April, he and first lady Michelle Obama spent a weekend in Ashville, N.C., with Nesbitt, Whitaker and their wives.

He’s also in constant contact with his Chicago friend Valerie Jarrett, who came to his White House as a senior adviser and is frequently in his tight social circle. When he vacationed in August on Martha’s Vineyard, Jarrett went too, catching a ride up on Air Force One, then playing Scrabble with Obama and dining with him.

Obama does play golf and basketball regularly — something that links him to millions of like-minded jocks across the land.

However, he plays basketball in closed-off gyms, usually with close friends and aides such as Reggie Love, a former Duke University player who’s Obama’s personal aide, and Arne Duncan, Obama’s Secretary of Education, who played hoops for Harvard and for pro teams in Australia.

When home, Obama plays golf on courses at Andrews Air Force Base or the Army’s Fort Belvoir, far from prying eyes and media cameras. There, too, he usually plays with close friends or aides such as Marvin Nicholson, the White House trip director, and Ben Finkenbinder, who works in the press office.

One way he reaches out beyond his circle is by reading letters from ordinary Americans, 10 of them selected daily by staff and given to him each evening in a folder. "Some of them just break my heart," he said of them. "Some of them provide me encouragement and inspiration."

And he’s involved with his daughters. He frequently attends events at their school — his motorcade stops for red lights on these unofficial treks — and he recently started a regular Sunday trek to a private gym to play basketball with them. "His girls keep him pretty grounded," Gibbs said.

Obama meets ordinary Americans during his travels around the country, but those interactions are limited. Often they’re just a handshake and a smile for a cell phone camera during a stop in a diner or bakery. He often buys food, paying cash and leaving big tips. He seldom stays to eat.

On a recent trip to Winston-Salem, N.C., for example, he spent a total of two hours and 49 minutes on the ground, and about 40 minutes of that was in his limousine.

On a November trip to Kokomo, Ind., he went to a firehouse, an elementary school, an auto plant and a bakery and was back on Air Force One in three hours and 45 minutes. His stop at Sycamore Elementary lasted seven minutes.

And on a September trek to suburban Fairfax, Va., as part of his Backyard Tour to meet with regular people, he arrived in a family’s yard at 1:42 p.m., spoke for 10 minutes, then answered questions for an hour and was back in the car at 3:21 p.m., headed back to the White House.

"I don’t know that you totally judge it by time," Gibbs said. "Part of it is the quality of the interaction. Talking to someone on a factory floor is important, talking to somebody at a cash register at a bakery when you’re there."

Quick stops or not, Obama plans more of them in 2011. "His goal is not necessarily to spend more time, it’s to do more trips," Gibbs said.

"There are more things that we can do to make sure that I’m getting out of here," Obama said. "Getting out of here is good for me, too."