WASHINGTON -- Barack Obama hits the exit early at glitzy fundraisers with rock stars. He makes only brief small talk in a roomful of supporters or at a rope line. He rarely rewards a supporter, donor or lawmaker with a game of golf, a drink at the White House or a trip to the presidential retreat at Camp David.

Instead, the 44th president of the United States keeps to his close circle of friends and advisors, rarely straying outside those comfortable confines to schmooze at parties, on Capitol Hill or on K Street.

He is, by his own admission, a loner.

Critics — and even some supporters — attribute Obama’s failure to achieve all that he promised in nearly four years, first with a Congress controlled by his party and later with a sharply divided one, to his detached personality.

He’s been unable to implement permanent tax cuts for the middle class, overhaul the immigration system or significantly reduce the ever-growing budget deficit. His achievements, such as passing a federal healthcare overhaul and a stimulus package designed to boost the economy, came with little or no Republican support.

Obama isn’t one to lobby members of Congress on his proposals. When the government was on the verge of running out of money to pay its bills last year, he took a seat at the table to talk about raising the debt ceiling. His ally, Senate Majority Leader Harry Reid, D-Nev., asked him to leave the White House meeting after realizing that congressional leaders would be better off hashing out a deal without him, according to a new book by journalist Bob Woodward.

Privately, Democrats on Capitol Hill grumble that they rarely have heard from Obama since he was sworn into office in January 2009, though publicly they downplay problems.

Rep. Xavier Becerra, D-Calif., one of Obama’s biggest surrogates in the Hispanic community, acknowledged that other presidents have done more networking over drinks or dinner, but he said he didn’t fault Obama for preferring to spend time at home with his family.

“The president decides to read to his daughters, and have dinner with his wife and daughters, instead of maybe go have drinks with senators or House members,” he said.

But Obama, who brought together new voters and a new coalition of supporters to achieve his historic election in 2008, has struggled to keep those supporters after four years without any access.

Neera Tanden, former domestic policy director for Obama’s campaign who now runs the Center for American Progress, a left-leaning research center in Washington, likened the president’s relationship to politics as “Bill Gates without liking computers” in a recent interview in New York magazine.

“The truth is, Obama doesn’t call anyone, and he’s not close to almost anyone,” she said. “It’s stunning that he’s in politics, because he really doesn’t like people.” She later apologized for her bluntness.

The White House and the Obama campaign declined to comment for this story.

Sen. Orrin Hatch, R-Utah, said he was “moved” to be invited to the White House three days after Obama’s inauguration to meet with the new president and vice president as well as Cabinet members. But, he said, that was the beginning and the end of the White House’s attempts to reach out to him. He said he’d been invited to the White House with other senators from time to time, but usually after a decision or policy, such as the healthcare bill, already had been finalized.