WASHINGTON (JTA) — During his 30 years in the clubby confines of the U.S. Senate, Arlen Specter never lost his acerbic prosecutorial zeal, friends and associates say.

The insistent questions, the commitment to independence that made the longtime Pennsylvania senator a critical player in recent U.S. history, ultimately did in his career. In his 2010 bid for a sixth term, Specter lost the support of both Democrats and Republicans.

Specter, who had been the longest-serving U.S. senator from his state, died Sunday of complications from non-Hodgkin’s lymphoma. He was 82.

His iconoclasm was his brand, from the outset of his career, when he made a name for himself as the young Philadelphia assistant district attorney on the Warren Commission who first postulated that a single bullet hit both President John F. Kennedy and Texas Gov. John Connally.

And he wore his independence as a badge of honor: The pro-choice Republican who helped fell Robert Bork’s nomination to the U.S. Supreme Court, and then ensured Clarence Thomas’ ascension by leading what many liberal groups saw as the smearing of Anita Hill, a one-time aide to Thomas who had accused the former head of the Equal Employment Opportunity Commission of sexually harassing her. The pro-Israel stalwart who enjoyed his one-on-ones with some of the Middle East’s most bloodstained tyrants.

Running for district attorney in Philadelphia in 1965, he left the Democratic Party, but returned in 2009, frustrated with what he said was the Republican Party’s lurch rightward. Specter the Democrat helped pass President Obama’s health care reforms.

“He would tell me, ‘Every morning I wake up I look in the mirror and I see the toughest guy in politics,’ ” recalled Morton Klein, the president of the Zionist Organization of America who first lobbied and then befriended Specter.

Specter, who represented Pennsylvania in the Senate from 1981 to 2011, was shaped by his childhood as the only Jewish kid in his class in a small Midwestern town, Russell, Kan., said David Brog, a longtime aide to Specter who eventually rose to be his chief of staff.

“He was a tough Jew,” Brog said. Specter’s upbringing — helping out his father, a peddler and scrap metal business owner, when he was barely beyond toddler age — was a factor in his pro-Israel leadership, Brog said.

“He saw a little of Israel in himself as the only Jew in his class in Russell,” he said.

Although his sisters were Orthodox Jewish, Specter himself was not outwardly religious, though he had a strong sense of Jewish identity.

Brog noted that on his visits to the Jewish state, Specter would make a point of visiting the grave of his father, who came to the United States from what is now Ukraine, and who wished to be buried in Israel.

Specter was a congressional leader in advancing the cause of Soviet Jews, recalled Mark Levin, who directs NCSJ, the former National Council on Soviet Jewry.

“He had a particular interest in addressing these issues through legal means,” Levin said, particularly by leveraging international human rights laws. Specter would grill his interlocutors from the Soviet Jewry activist movement, asking them to come up with new avenues to leverage the Soviet Union and other European states.

“He wanted to know what more could be done, at the most difficult time when so few people were getting out,” Levin said. “What more could we do, whom do we need to speak to, what do we need to focus on? He was tough but fair.”

Specter also helped preserve the Lautenberg Amendment, named for Sen. Frank Lautenberg (D-N.J.), which eased immigration for refugees from persecution. Designed as a way to advance the exodus of Soviet Jews, Specter extended the amendment to minorities from other nations, including Iran.

“A prescient leader, he understood early on that religious minorities within Iran needed special protection,” said a statement from the Hebrew Immigrant Aid Society. “The senator never forgot his Jewish roots, and his legacy within the Jewish community is great.”

Specter throughout his career was a pro-Israel leader, in recent years leading efforts to condition aid to the Palestinian Authority on its peace process performance. He also aimed to protect Jewish students on campuses from anti-Israel harassment.

An array of Jewish and pro-Israel groups mourned his passing.

“Time and time again, Sen. Specter worked to ensure that America’s ally had the resources necessary to defend herself and protect U.S. interests in the Middle East,” the American Israel Public Affairs Committee said in a statement. “He was a good friend of our organization and a leading architect of the congressional bond between our country and Israel.”

The Israeli Embassy in Washington called Specter “ an unswerving defender of the Jewish State and a stalwart advocate of peace.”

Yet Specter also courted the region’s tyrants, including Iraq’s Saddam Hussein and the Assads in Syria. He longed for a role brokering peace between Israel and Syria, even after his departure from the Senate.

“He visited these tyrants and he was convinced that he could convince them to moderate their policies,” Klein said. “And as we know, he never did.”

Brog said that Specter relished, from his days as a prosecutor, the challenge of going toe to toe with bad guys and getting them to stand down.

“He and Hafez Assad would sit for hours on end drinking tea, seeing who would need to go for a bathroom break first,” Brog said, referring to the late Syrian strongman and father of the country’s current ruler, Bashar Assad.

More seriously, Brog said, Specter was committed to creating an environment friendly to peacemaking for Israel by forging a deal with its most recalcitrant neighbor.

“The prize was, if you could get Syria, the most extreme of Israel’s neighbors, to sign a peace deal, you could create a climate in the region,” he said.

Specter’s independence took a toll on his staff, Brog said.

“Every single vote he wanted a briefing on the merits without just knowing how the party wanted the vote,” he said.

Specter was an exacting boss, Brog said, and notorious for sending staffers packing.

“Those of us who stayed with him saw this as a very good thing,” said Brog, who now serves as executive director of Christians United for Israel. “I look at my professional standards from before and after, and I see how I grew as a professional.”

Nominees for the federal bench were a regular target of his difficult questions, said Sammie Moshenberg, the Washington director of the National Council of Jewish Women.

“He was always independent and was proud of the fact that he went with his conscience,” she said.

Moshenberg found his tough questions gratifying when Specter grilled nominees on reproductive rights, but recalled being “infuriated” when he accused Hill of perjuring herself in accusing Thomas of sexual harassment.

“I remember standing in the Senate reception room waiting for him to vote and thanking him at times, and expressing disappointment at other times,” she said. “Many times I got to thank him.”

As the political climate grew more polarized, Specter found himself assailed by the left and the right. In 2004 he barely fended off a Republican primary challenge from his right by Rep. Pat Toomey.

Five years later, realizing he would likely not be able to beat Toomey again, Specter switched parties, saying the GOP had “moved far to the right.” Yet the Democratic Party proved no more welcoming; he lost in the 2010 primary to Rep. Joe Sestak, who in turn was defeated by Toomey in the general election.

The Jewish affiliates of both parties issued statements commemorating Specter’s career. Each emphasized different aspects of his career — the National Jewish Democratic Council called him a “crucial voice of moderation” and the Republican Jewish Coalition said he was a “staunch supporter of Israel.”

But the groups echoed one another in describing Specter’s higher calling: The RJC noted that he was a “devoted public servant,” and the NJDC called him a “consummate public servant.”