As the Ground Shifts, Biden Plays a Bigger Role

For two hours, Mr. Biden had been going back and forth with furious members of his own party over President Obama’s deal with Republicans on tax cuts. In a basement room at the Capitol, Mr. Biden was trying to convince Democrats that the deal was the best one they were going to get.

Then Representative Anthony Weiner of New York got up and asserted that Mr. Obama was acting like a “negotiator in chief” instead of a “leader” who gets things done.

Mr. Biden erupted. “There’s no goddamned way I’m going to stand here and talk about the president like that,” the vice president said, according to two people in the room.

In the annals of bickering among Democrats, the exchange between Mr. Biden and Mr. Weiner was mild. But it highlights the distance that Mr. Biden and Mr. Obama have traveled since they ran against each other in the 2008 Democratic primaries, a campaign season that Mr. Biden kicked off by saying Mr. Obama was “the first mainstream African-American who is articulate and bright and clean and a nice-looking guy.”

Now, at the halfway point of a first term in which Mr. Obama has mostly relied on the counsel of a tightly closed inner circle, Mr. Biden is taking a more prominent and influential role. With the departure of Rahm Emanuel as chief of staff and Mr. Obama’s need to negotiate with Congressional Republicans if he is to advance his agenda, the president is increasingly using Mr. Biden as a multipurpose emissary while continuing to seek his counsel behind the scenes.

Mr. Biden not only played an important role in negotiating the tax deal with Republicans and trying to sell it to Democrats, but also was one of the people in the West Wing who urged Mr. Obama to try to find a compromise on the issue in the first place, aides said.

The president is at a crucial point, with a restive party that is trying to figure out what its role and relationship with the White House will be leading up to the 2012 elections.

Among Democrats on Capitol Hill, Mr. Biden’s role in the back-channel compromise with Republicans on tax cuts has engendered some resentment, along with questions about whether he will encourage further accommodation with Republicans or serve as a liberal counterweight to those in the White House who are advocating a move to the center.

Republicans are still assessing how powerful a player he will be as the White House adapts to a divided government. But in both parties, he is seen if nothing else as someone well positioned to shuttle between Congress and the West Wing.

“I guarantee you, Joe’s walking back to the White House with a head full of information,” said Senator Christopher J. Dodd, a Connecticut Democrat and close friend of Mr. Biden. The president, Mr. Dodd said, needs Mr. Biden’s wide network because he “just doesn’t have the personal relationships that Joe has.”

Or, as Mr. Weiner put it in an interview, “Biden brings everything that Rahm Emanuel brings, but the major difference is everyone likes Joe Biden.”

While Mr. Biden has credibility with the Democratic left, his long record in the Senate has enough moments in which he proved willing to work with or give ground to Republicans that they view him as less dogmatic than many other administration officials.

Mr. Biden alienated some of the left when he led the Senate Judiciary Committee’s hearings for Clarence Thomas’s nomination to the Supreme Court in 1991. While he voted against confirmation, Mr. Biden made decisions during the hearings, including not allowing testimony about pornography rentals, that many critics believed helped Justice Thomas weather the confirmation process.

Beyond his behind-the-scenes role in negotiating the tax deal with Republicans — a path that Mr. Biden and Mr. Obama decided on in a recent conversation at the White House, aides say — the vice president has also been trying to win Republican votes in the Senate for ratification of the so-called New Start nuclear arms treaty with Russia.

That background for compromise is now being put to use at the White House, from Mr. Biden’s diplomatic mission to try to soothe the angry House Democrats to his secret shuttling between his boss and the Republican Senate leader, Mitch McConnell, to iron out the tax deal.

Mr. Biden took the lead in nudging Iraq’s leaders into forming a new coalition government. He has been given the task of navigating growing tensions in Lebanon. And while Mr. Obama rejected Mr. Biden’s recommendation of a narrowly focused counterterrorism strategy for Afghanistan in favor of a more expansive counterinsurgency approach, the halting pace of progress in Afghanistan has left some administration officials wondering if the president might not eventually come around to Mr. Biden’s way of thinking.