When she lost the nomination, he supported then-Sen. Barack Obama -- ardently. "I voted for Obama, I made donations, I had phone banks, I set up at condominiums and (sent) thousands of emails," said Barr, a 74-year-old south Florida resident. "By the third year, I realized I made a humongous mistake."
The next election, he voted for Republican nominee Mitt Romney as a rejection of Obama's policies toward Israel. And as the 2016 election nears, Barr has no plans to vote for Clinton, the Democratic front-runner.
Republicans have seized on Obama's rocky relationship with Israeli Prime Minister Benjamin Netanyahu, who has publicly clashed with the President over Iran and the Palestinians, to argue that Obama has not been a strong ally of the Jewish state. And they're extending that criticism to Clinton, who carried out Obama's policies for four years in her role as his secretary of state.
Though Jews overwhelmingly vote Democrat, conversations with Jewish voters at Ben's Kosher Delicatessen in Boca Raton suggested the GOP strategy is more than just wishful thinking. Patrons expressed deep dissatisfaction with Obama's dealings with Israel, and those feelings have tainted their impression of the former New York senator, who won Florida's Jewish voters 2-to-1 over Obama in the 2008 primary.
Hal Silverman, a 78-year-old Brooklyn transplant who's lived in Boca Raton for the last 25 years, was one of those Democrats who voted for Obama in 2008 and 2012. In the latter contest, the President won the county -- Palm Beach -- by 17 points, thanks in part to the Jewish vote; the county has the fourth-highest number of Jews in the country.
"I've always voted straight Democratic Party unless I particularly knew one or two of the people running who weren't Democrats who were better for the community," he explained on a sunny Friday outside Ben's, where CNN spoke with a dozen Jewish voters about Clinton and the 2016 election.
Disaffection over Middle East policy
But U.S. policy under Obama toward Israel and Iran has turned Silverman off from the President.
And from Clinton: "Absolutely, absolutely," Silverman said.
Ellen and Bob Hausner, a married couple of nearly 30 years divided along party lines, said they have finally found a point of agreement -- or mutual disapproval -- on politics. (Hint: She's a pantsuit aficionado and the leading Democratic candidate for president.)
"I would say a lot of people are disenchanted with the Democratic Party. People down here in particular," said Ellen, the Democrat in the family. "They have issues with the Iran deal now. They have issues with what's happening domestically, and they just have lost confidence and respect in Obama. And I don't think they're particularly supportive of Hillary."
Bob, a Republican, gleefully eyed his wife in agreement.
Sitting inside the deli after eating what he called "the finest pastrami," Eugene Rudoy said his 2008 support for Hillary Clinton is no barometer of his feelings on the 2016 race.
"If you bring me to today, I wouldn't support her," the 84-year-old Boyton Beach resident said. "She's just an extension of Obama."
Clinton is already working to fight that perception when it comes to Israel, cognizant of Jewish voters' distrust of Obama's policies toward Israel and Iran.
While Clinton backs Obama's Iran deal -- which Israel opposes -- the former secretary of state, who helped launch the negotiations, committed to ensuring Israel's security and to confronting Iranian aggression in the same breath as she announced her support for the deal in September.
And in a letter to several top Jewish donors and pro-Israel leaders this summer, Clinton expressed her staunch opposition to calls to boycott Israel and pledged to fight the boycott movement.
The Clinton campaign on Thursday dismissed any concern that its support among Jewish voters could be in jeopardy.
Clinton touts support for Israel
Clinton campaign spokesman Jesse Lehrich touted her "commitment to our unshakeable alliance with Israel," citing her work to promote security cooperation with Israel and brokering a ceasefire that ended clashes between Israel and Hamas in 2012.
"Hillary Clinton has always had a deep connection to Jewish-American voters, and she is honored to continue to have strong support from that community," Lehrich said in an email to CNN. "She's made clear that continuing to strengthen this partnership will be a top priority of her presidency. For her, this goes beyond policy; it's personal."
Despite talk of a slide in Jewish support for the Democratic Party since Obama's election in 2008, Jewish voters still turned out in droves for Obama in 2012. Obama's share of the Jewish vote slipped to 69% from 74%, based on exit polling, a fall that mimicked drops among other typically pro-Democratic voting blocs.
Though Jews make up about 2% of the national population, they comprised 5% of voters in Florida that year, also according to exit polls. While still a small fraction of the total, every vote in the crucial battleground state is hotly contested. Florida's Jewish population also tends to be older and less progressive than Jews in many other parts of the country, making them more inclined toward hawkish positions on the Middle East.
Kenneth Wald, a political science professor at the University of Florida who has studied the Jewish vote throughout his career, said that while there's a clear "unease" about Obama's policies toward Israel among American Jews, he would "be surprised if that crystallizes into a significant political shift."
"For as long as I've been studying Jewish voters, people keep telling me this is the year we're going to see the transformation," he said. "I just think that this is stuff that happens between elections and the atmosphere changes when you actually get into choice."
And the Clintons, he said, still enjoy "a very deep well of attachment" among Jewish voters.
Unfortunately for Clinton, though, her staunchest supporter outside the Boca Raton delicatessen last Friday refused to be named for fear that her friends would mistakenly think she's anti-Israel.
"A lot of my friends, family -- some of whom are Democrats -- do not feel that Obama is for Israel. It's plain and simple," she said.
She said she was not concerned "at all" about the strength of Clinton's support for Israel and said that while she waffles on whether the Iran deal is good, she is hopeful it will result in a peaceful outcome.
She also hopes that one of her own reasons for supporting Clinton will resonate with fellow Jewish voters.
"People know the Clintons and I think that that will reign over anything else," she said. "You know, voting for Hillary is voting for two presidents, not one president. So you're getting two for the price of one. And a lot of Jewish voters loved Bill."