WASHINGTON — Nathan Diament learned two things 22 years ago while watching Barack Obama play pickup basketball at the Harvard Law School gym.

“He was a generous passer,” he said of the school’s Law Review editor and the future U.S. president. “He was competitive, but at an appropriate level of competitiveness. He didn’t get in your face.”

It’s an acquaintance that continues to serve Diament to this day on his mission of representing a minority within a minority — he has headed the Orthodox Union’s Washington office since it opened in 1998.

Most recently, it culminated in a high-profile exchange between Orthodox leaders and Obama at the White House. Paving the way to such access is Diament, a respected veteran of the Jewish professional cadre in the nation’s capital.

“Nathan was one of the folks who said that direct dialogue between the Orthodox community and senior administration officials could lead us to common ground,” Jarrod Bernstein, the White House liaison to the Jewish community, told JTA. “He has novel approaches to vexing policy questions.”

It’s a skill that is valued by his bosses in New York.

Rabbi Steven Weil, OU’s executive vice president, said Diament managed to reconcile a dilemma for the group: its advocacy for state funding of schools, despite adamant resistance to such funding among Democrats. Diament was able to help win bipartisan support for Homeland Security grants aimed at securing non-profits, which included help for Jewish day schools.

“Because he has been in D.C. as long as he has, he has serious relationships not only with key legislators but with staff as well,” Weil said.

Jewish Federations of North America and Agudath Israel of America also led the push for the Homeland Security grants. William Daroff, the JFNA’s Washington director, called Diament the team’s “critical thinker” in working out strategies to build alliances in Congress.

Diament started out with the OU in the mid-1990s in New York helping to make its case to the national government. Then he had to convince skeptical superiors that he needed to be in Washington on a full-time basis.

An unexpected boost came in 1998 when U.S. Sen. Joseph Lieberman, then a Democrat of Connecticut, wondered aloud at an OU centennial event why the group had no representation in Washington. Lieberman in an email said that Diament had made the OU a “significant presence” in the capital by forging “creative coalitions.”

Chabad-Lubavitch has reached out to leaders here since the late 1970s and Agudath Israel of America opened its office in the 1980s. But representatives of both those groups say that Diament’s added value for the Orthodox and general Jewish community is his enthusiastic understanding of the sometimes arcane workings of government.

“There is strength in numbers,” said Rabbi Abba Cohen, the director of Agudah’s office. “Nathan is knowledgeable, capable and dedicated, and by skillfully using these assets has been a boon to Orthodox advocacy on the federal level.”

Policymakers say Diament — and by extension the Orthodox Union — bring nuance to the table in a town that otherwise is flooded with the perspective of Jews as liberals who tend to vote Democratic.

Elliott Abrams, a deputy national security adviser under President George W. Bush, recalled one such encounter in late 2007 with himself, an OU delegation led by Diament and the national security adviser, Stephen Hadley. Hadley had been apprised of Israel’s national and security case for its claim to all of Jerusalem, but something was missing: the religious claim.

“Most of the discussions of all this are conducted among secular Jews, and they are political rather than religious,” Abrams said. “This was bringing some new light to the situation for Steve Hadley.”

The OU’s tough posture at the time on Jerusalem earned the group a rebuke from then-Israeli Prime Minister Ehud Olmert, who bristled at the notion of a Diaspora organization staking a claim to how Israel should deal with Jerusalem.

Abrams said the OU perspective adds something else to Washington as well.

“On religious freedom and domestic policy issues, you have an additional Jewish perspective and it is not always the same” as the prevalent voice among more liberal Jews, he said.

That “Jewish perspective” — favoring fewer restrictions on government-church interactions — is likelier to find resonance with Republicans, as is the OU’s generally skeptical stand on peace talks with the Palestinians.

That made Diament’s job easier when George W. Bush was president and Republicans, with their similar outlook, led Congress. As Democrats rose to prominence, first by taking Congress in 2006 and then with Obama’s election in 2008, Diament found himself making the case to the Orthodox community, which tends to favor Republicans, that it was worth reaching out to Democrats.

“There’s definitely people in the community who think Obama’s terrible on Israel and who would like to see us play a more partisan role than we could,” he said.

So at meetings in synagogues and to audiences across America, he tries to tweak apart the myth from the facts, noting the real differences between the Obama administration and the Israeli government on settlements, for instance, but also the closeness in the defense alliance.

Diament’s ability to walk that line is a result of an upbringing less inclined to the insularity of some in the Orthodox community, said Rabbi David Saperstein, the director of the Reform movement’s Religious Action Center.

Diament’s father was an Orthodox rabbi at a Conservative shul in Lynbrook, N.Y., where Saperstein’s father helmed a Reform synagogue.

“He works well with people that disagree with him,” said Saperstein, who served with Diament on a White House advisory council on faith-based initiatives.

In recent years, Diament’s relationship with Obama certainly has helped. Diament was one of the few to recognize Obama when the candidate for the U.S. Senate seat from Illinois attended an American Israel Public Affairs Committee policy forum in 2004. He relieved Obama from the awkwardness of standing alone in the conference hall.

Obama returned the favor on his first day in the Senate, recognizing Diament as he strode through the Senate office buildings and hugging him.

Sources close to both men emphasize that the relationship is one of friendly acquaintances.

Still, some in the Orthodox community have suggested that Diament is too close to Democrats. Congressional Democrats, in turn, wonder why Diament holds back on advocating on issues in which liberal and Orthodox interests unite, like federal money for the poor.

Diament did campaign against Obama’s mandate to extend contraceptive coverage to employees of religiously-run institutions like orphanages and hospitals. The stance baffled some Democrats — the Orthodox, in most cases, allow contraceptive use — but Diament said it was a principled policy against government interference with religious institutions.

At the June meeting of Obama and Orthodox leaders, Diament elicited laughter by saying that the stand also was a quid pro quo for Roman Catholics who joined the OU last year in successfully pushing back San Francisco’s proposed ban on circumcision.

But the meeting also had tense moments, such as when some participants felt that Obama appeared dismissive of the desire for large families. Others worried that the president seemed to condescend when he said he was more knowledgeable about Jewish matters than his predecessors.

At meeting’s end, Obama and the Orthodox leaders were still entrenched with their differing views. But Diament had brought them together to at least address mutual suspicions.

Diament speaks of congregation rabbis who attended the White House meeting.

“They told me they went back to congregants who were fiercely anti-Obama — and they were proud and happy the meeting took place,” he said.