Mr. Obama left “frustrated that while he was putting out ways to bridge the problem

Tempers were fraying in the White House Cabinet Room as night turned into morning on Jan. 15. President Obama had been cloistered nearly all day with House and Senate Democrats, playing "marriage counselor," an aide said, as he coaxed, cajoled and prodded them on a health care overhaul As the clock neared 1 a.m., the two sides were at an impasse. Mr. Obama stood up. " ‘See what you guys can figure out,’ " one participant remembers him saying, adding that the failed effort left the president mad. Another Democrat who was there, Representative Henry A. Waxman of California, said Mr. Obama left "frustrated that while he was putting out ways to bridge the problem, we hadn’t reached a conclusion." Ever since his days as a young community organizer in Chicago, Mr. Obama has held fast to the belief that by listening carefully and appealing to reason he can bring people together to get results, an approach that in Washington has often come up short. He is not showing any signs of changing his style. But he is facing perhaps the toughest test yet of his powers of persuasion: winning the votes he needs, in the face of unified Republican opposition and a deteriorating climate for Democrats, to push his health care measure through a skittish Congress. Mr. Obama has not been the sort to bludgeon his party into following his lead or to intimidate reluctant legislators. And while he has often succeeded by relying on Democratic leaders in Congress to do his bidding — the House and Senate, after all, both passed versions of the health legislation last year — it is not clear whether his gentle, consensus-building style will be enough. "I wouldn’t mind seeing a little more toughness here or there," said Representative Louise M. Slaughter, a New York Democrat, who contends that if Mr. Obama had pushed the Senate harder last year, the bill would have been law by now. Like many Democrats in Congress, she praises Mr. Obama as intellectually gifted and a generous listener. But "if you are asking me if he dominates the room," she said, "I would have to say no." White House officials strongly resist any suggestion that Mr. Obama is not tough enough, and they say the days are gone when a president can simply browbeat his own party into submission, especially on an issue as complex as health care. "If the president weren’t tough, if the president weren’t committed, if the president didn’t believe that this was an imperative for the future of American families, businesses and the sustainability of our budget, this thing would have been dead six months ago," David Axelrod, Mr. Obama’s senior adviser, said in an interview. "I would love to live in a world where the president could snap his fingers or even twist arms and make change happen, but in this great democracy of ours, that’s not the way it is." One of the most persistent criticisms of Mr. Obama, especially on health care, is that he has given Congress too much latitude to engage in backroom deal-making and expedient trade-offs. His critics suggest that they want him to step forward more assertively to put his stamp on the process and the legislation. But his defenders and some historians say that perhaps more than any modern president since Lyndon B. Johnson, Mr. Obama has been aggressive in trying to work his will with Congress. During his 13-month-old presidency, he has had countless one-on-one meetings with lawmakers — a technique that some scholars and strategists say evokes memories of Johnson, though their styles could hardly be more different. "People make the L.B.J. analogy," said John D. Podesta, who worked as chief of staff in the Clinton White House, "but the world is a lot different than it was during the 1960s. The president actually has to bring people along because they think it’s the right thing to do, because they think it’s in the interest of the country but also their own self-interest. His style is to convince people, not threaten them." If Johnson was a physical force — an arm around the shoulder, a full-body lean, a finger poking into the chest — Mr. Obama is an intellectual one. Members of Congress do not find him intimidating; they are more apt, said Senator Byron L. Dorgan, Democrat of North Dakota, to view him as "a friend." And while he shows occasional flashes of anger — "There is a sort of steel in his voice," said Representative Steny H. Hoyer, the House Democratic leader from Maryland — his emotions are always contained. While courting Senator Olympia J. Snowe, Republican of Maine, on the health care bill last year, Mr. Obama kept her in the Oval Office for an extraordinary 90 minutes. (She voted no.) When Senator John D. Rockefeller IV, a West Virginia Democrat, hinted that he would vote against the Finance Committee’s health bill, Mr. Obama laid the personal attention on thick. During their private Oval Office meeting, they sat side by side, the senator said, in front of the fireplace and underneath a portrait of George Washington, in the blue and beige striped chairs Mr. Obama uses when he meets with foreign leaders. Mr. Obama briefly rested his hand on the senator’s arm when making an important point — the same kind of gesture, Mr. Rockefeller said, that he uses to connect with voters back home. He made no promises, but Mr. Obama got his vote. "Un-dictatorial, un-Caesar-like," he said, describing Mr. Obama’s style. Gerald Kellman, who trained Mr. Obama as a community organizer in Chicago and taught him