Sen. Benjamin L. Cardin (Md.), the ranking Democrat on the Foreign Relations Committee, is a key voice in the debate over the Iran nuclear agreement. Cardin has said he plans to make a decision on his vote within the next few days. (Andrew Harnik/AP)

Even as his colleague from Maryland on Wednesday provided the final vote needed for President Obama’s Iran deal to survive, Sen. Benjamin L. Cardin (D-Md.) continues to wrestle with whether to support the deal — a decision that has pitted him against his rabbi, riled his constituents and consumed him for much of the past month.

“When Senator Cardin goes to synagogue, he hears about this. When he goes out to dinner, he hears about it. When he sees his grandchildren, he hears about it,” said Ronald Halber, executive director of the Jewish Community Relations Council of Greater Washington. “It’s not that he gets a chance to escape.”

Both supporters and opponents who have lobbied Cardin say they have no idea where the senator stands.

“Cardin is in a tough situation,” one Democratic staffer on Capitol Hill said. “I think he sort of feels like the responsible thing to do as the ranking member on Foreign Relations and a member of the U.S. Senate is to support the deal, but as a strong supporter of Israel and a leader in a Jewish community, the right thing to do is to vote against it.”

Proponents and opponents saw Cardin as a key vote. Opponents in particular wanted Cardin to come out against the deal before the White House managed to cobble together support from 34 senators — enough to allow Obama to veto any vote against the bill, without fear of an override.

The White House is still pushing for at least seven more votes in favor of the deal, which would allow proponents to block any vote against it.

But Cardin remained undecided as of Wednesday morning, when Maryland’s senior senator, Barbara Mikulski (D), announced she would be the crucial 34th vote.

Cardin is the ranking Democrat on the Senate Foreign Relations Committee. His opinion about the pact’s policy specifics holds considerable weight. As a deeply observant and prominent member of Baltimore’s Jewish community, and a staunch supporter of Israel, he is an influential voice on a deal that the government of Israeli Prime Minister Benjamin Netanyahu has vociferously opposed.

The American Israel Public Affairs Committee staged a rally of more than 1,600 people at Cardin’s synagogue in suburban Baltimore on Tuesday night, urging Cardin and other senators who were still undecided to oppose the deal.

“It’s our belief that if we can move the members of this delegation, it will have an impact on other delegations,” said Howard Kohr, AIPAC’s executive director.

Despite the group’s efforts, Mikulski announced her support for the deal the next morning.

“AIPAC did what they thought was right,” Cardin said Wednesday, after appearing at a forum to discuss the Iran deal at the University of Maryland at College Park. He insisted that his decision on whether to support the deal will be based on conscience, not political strategy.

Rabbi Mitchell Wohlberg, who spoke at AIPAC’s rally Tuesday, said he has called both Cardin and the senator’s wife multiple times to express his vehement opposition to the Iran deal and his hope that the senator will oppose it. Cardin said he still plans to attend Rosh Hashanah services later this month at the synagogue, where Wohlberg will speak against the deal.

“He has very strong views on this,” said Cardin, who has a close, personal relationship with Wohlberg. “He has every right to do what he’s doing . . . his view goes in the equation like everyone else.”

Supporters of the Iran deal are also campaigning actively to persuade Cardin and others; the liberal pro-Israel group J Street has spent $450,000 on ads on Baltimore television urging people to back the deal.

“It’s been intense,” Cardin said Tuesday at a forum on the deal held at Johns Hopkins University. “Most is healthy, but there’s been some people on both sides that I think have gone further than is useful.”

Treasury Secretary Jack Lew, an Orthodox Jew, was heckled when he defended the deal at a recent event in New York.

At the University of Maryland on Wednesday, Cardin questioned polls of Jewish public opinion on either side. “I don’t believe or think any polling is accurate of Jewish Americans,” he said. But, he added, “I think I represent the community. They’re divided; I’m divided.”

Cardin has said he plans to make a decision within the next few days.

He told the Johns Hopkins students that assuming the deal survives, even its opponents in Congress should rally behind the president — just as he rallied behind President George W. Bush during the Iraq war, even though he voted against it.

“When this is over, we’ve got to come together and support our president,” Cardin said. “And I intend to play a pretty active role in that.”