Senator Obama was winning more than 90% percent of the black vote in some primaries against Senator Clinton, but his backing among a tiny subset of that minority — black partners at major law firms — may be even higher.

Come fall, many of New York’s and Washington, D.C.’s most prominent African-American attorneys are more likely to be spotted at Obama campaign headquarters in the battleground states than at the U.S. courthouses on Pearl Street and Constitution Avenue.

At Covington & Burling’s Washington office, a Bronx-born former deputy attorney general, Eric Holder, is “consumed,” he said, by the search to select a vice presidential candidate to run alongside Mr. Obama. Mr. Holder, a campaign co-chairman, is frequently mentioned as a possible attorney general if Mr. Obama wins.

In Midtown Manhattan, at the firm Paul, Weiss, Rifkind, Wharton & Garrison, a television in the office of partner Jeh Johnson, a top Obama fund-raiser and policy adviser, is frequently tuned to political news. On occasion, Mr. Johnson himself ducks out of his office to head to the nearby studios of Fox News Channel or MSNBC for an on-air appearance as an Obama campaign representative to discuss the campaign focus of the day, be it Iowa or Iran.

A few blocks north is one of Dewey & LeBoeuf’s Manhattan offices, where another linchpin of Mr. Obama’s campaign efforts in New York practices law. Gordon Davis, a former city parks commissioner and former president of Lincoln Center, is, along with Mr. Johnson and a handful of other big firm lawyers in New York, committed to raising more than $250,000 each for Mr. Obama.

“I’ll ask anybody for money, that’s for sure,” Mr. Davis said, describing the central tenet of a fund-raising strategy that once led him, while seated on an examining table, to persuade a doctor he had never before met to contribute to Mr. Obama.

Messrs. Davis and Johnson have been backing Mr. Obama since early 2007, at a time when many New Yorkers perceived Senator Clinton as the front-runner.

The efforts of both men have extended far beyond raising money, providing introductions for the candidate, and preparing advice on election law. Both men have put in time as campaign grunts, traveling across state lines to hand out leaflets and knock on doors.

The work isn’t always encouraging. At times, there have been suggestions that racial animosity sways voters. During a campaign trip with his son to Northeast Philadelphia, Mr. Johnson said that the “hostility to us and Barack was palpable.”

Mr. Johnson recalled the reaction he received from one man in particular whom he approached in the hopes of discussing the Obama campaign. The man, who was white, was engaged in “sucking back beers on his front lawn.”

The man responded to Mr. Johnson with a complaint: “Blacks get all the city jobs in Philadelphia,” Mr. Johnson recalled.

At the vast majority of large offices in New York City, black lawyers represent less than 3% of the total number of law firm partners. Even so, the total number of black partners at large New York City firms today is on a different order than what it was a generation ago: When Mr. Davis made partner in 1983 at Lord, Day & Lord, he became the fifth black partner then working at a major firm in the entire city.

“In 1983, of the few of us that were, none of us were thinking about running for president,” Mr. Davis said. “It’s a different sense of horizon.”

Today the group of black law firm partners in New York City numbers about 125, according to several estimates. Generally, they meet twice a year at the Harvard Club, although Mr. Johnson convened the group in June to discuss the Obama campaign. The meeting drew about 35 members in person, along with many others listening in by conference call, Mr. Johnson said.

Other black law firm partners in New York who are active in campaigning for Mr. Obama include Arent Fox’s Darrell Gay and Fulbright & Jaworski’s Ralph Dawson, a superdelegate to the Democratic National Convention who has begun publicly supporting Mr. Obama after staying neutral throughout the primaries.

A partner at Frankfurt Kurnit Klein & Selz PC, Lisa Davis, who has co-hosted several fund-raisers for Mr. Obama, explained her support for Mr. Obama: “I said to myself that this is someone who represents my generation of lawyers, my generation of African-American professionals.”

In interviews, several black attorneys supporting Mr. Obama say they take pride in the fact that a black American may well win the presidency.

There is “the ethnic pride,” Mr. Holder said. “But what I do think is unique about Barack is that I think he’s tapped into something beyond his ethnicity. His notion of positive, significant change I think really resonates with African Americans, women, younger lawyers.”

Mr. Johnson, who served as the general counsel to the Air Force under President Clinton, said that the Obama campaign, rather than focusing on racial identity, was “going a long way to bridge the racial divide.”

“When I get retained to try a case in, say, Los Angeles, I think the calculus is different than it was eight years ago,” Mr. Johnson said. “I think there is less trepidation when hiring a person of color to be the first chair at the counsel’s table in a place where there’s likely to be a majority white jury.” He explained this perceived shift in terms of the visibility of Mr. Obama and prominent black officials in the Bush administration such as Secretary of State Powell and Secretary of State Rice.

At times, Mr. Johnson’s role in the campaign roams beyond any of the several titles which he holds. When attention was focused on Mr. Obama’s responses to inflammatory statements by his pastor, the Reverend Jeremiah Wright, Mr. Johnson wrote a personal letter to a fellow former Clinton administration official, Lanny Davis, which ended up on a CNN Web log.

Mr. Johnson wrote, reflecting on his own experience as a student at Morehouse College, that “those of us who participate in both the white and African-American experiences will very likely have a Jeremiah Wright in our lives.”

He wrote “here I am, a patriot who — I can honestly say — harbors no ‘anger’ or racial animosity toward anybody,” closing with a guarantee that “from what I know about Barack Obama, that he feels the same in his heart and soul.”

In several instances, Mr. Obama had to work for the support of this group. Mr. Johnson said that until he met Mr. Obama at a string of Democratic fund-raisers in 2006 he did not believe that the senator could be a viable candidate. As Mr. Johnson put it: “I was in the camp of the believing that he was the T-shirt of the week.”

Mr. Dawson, the superdelegate, said, referring to his decision not to pick between Mrs. Clinton and Mr. Obama until June, that he “felt both candidates were eminently well-qualified to be president of the United States and the real question was which candidate was best positioned to prevail in the fall.” Two other prominent black lawyers, a former U.S. attorney in Brooklyn now with Dorsey & Whitney, Zachary Carter, and a retired partner at Simpson Thacher, Conrad Harper, who was the first black president of the New York City bar association, both gave $2,300 to the Obama campaign this year after making contributions to Mrs. Clinton in the past.

For his part, Mr. Obama has courted lawyers, visiting the New York offices of Paul Weiss; Skadden, Arps, and Proskauer Rose in the last two years.

Among big firm lawyers, Mr. Obama’s support certainly isn’t limited to black attorneys. Skadden’s Preeta Bansal is a top policy adviser. Mayer Brown’s Andrew Schapiro has pledged to raise $250,000.

In June, more than 100 lawyers, many of whom had previously supported Mrs. Clinton’s bid, met at Skadden’s office to plan their efforts for Mr. Obama.

And the Republican candidates for president have drawn support among a few prominent black attorneys who have left law firms. The chairman of the board at Time Warner, Richard Parsons, who once was the managing partner of the New York firm Patterson, Belknap, Webb & Tyler, contributed $25,000 in May to the McCain Victory Committee. And the former deputy attorney general under President Bush, Larry Thompson, who is now general counsel of PepsiCo, had contributed to Mayor Giuliani’s bid.