NORTHAMPTON — Massachusetts Senator Elizabeth Warren, known as a longtime progressive, has recently made some on the left question her integrity after a controversial decision to endorse Hillary Clinton as the democratic presidential nominee.

Warren, who gave a talk on Sunday addressing income inequality at the WWII Club in Northampton, was greeted by legions of adoring fans, but also a small crowd of protesters who said they were deeply disenchanted with Warren's endorsement.

Outside the club at 50 Conz St., a crowd of "Bern feeling" supporters protested Warren's recent endorsement. The protesters were dressed all in black, to symbolize, they said, the mourning of who they thought Warren was.

As far as the protesters were concerned, Hillary Clinton may have all but clinched the democratic presidential nomination, but if there's one thing she won't secure its love from Sanders supporters like them.

"Never," was the most common response given to the question "Would you ever support Clinton in the general?"

Furthermore, the protesters felt Warren's support of Clinton seems to go against everything they thought she stood for.

"We feel that this is completely not in alignment with everything that she has been preaching her entire career," said Jaime Guerin, who has volunteered for the Sanders campaign and is a staunch believer in the senator's populist messages. "We're never going to have a government for the people as long as corporate interests continue to govern our politics," Guerin said.

Many of the protesters felt betrayed by Warren's endorsement of Clinton.

"For so long Elizabeth Warren has maintained positions that align with Bernie, and now she just seems to have abandoned that in favor of supporting the establishment's candidate," said Gale Brown, 38, a long-time fan of Sanders.

Brown points out that Warren's positions, which have often included critiques of corporate power, campaign finance laws, and income inequality, seem to be at odds with a candidate like Clinton who has formerly accepted generous contributions from banks and who has deep financial ties to a multitude of international corporations. "The positions that she had espoused before were for the people and doing what's right for the people," said Brown. "She was also critical of Hillary in the past, and now she endorses her? It just hard to say what her reasoning and motivation for that are. It calls her integrity into question," she said.

This sense of bafflement seemed to be the underlying feeling for many who were present at the protest.

"I have no idea why she did it," said Amy Bookbinder, 69, who could be seen holding a sign at the rally that said "Dear Elizabeth, Why? Love Amy." Bookbinder, who has been a longtime fan of Warren, says she's confounded by the senator's decision to endorse Clinton.

The crowd of protesters was diverse, and even featured "Moose," a Bernese Mountain Dog sporting a saggy Sanders t-shirt that read "Bernese for Bernie." Supporters assured passerby that he was one of the more enthusiastic fans of the "socialist" senator from Vermont.

Warren, who went on to give a speech that touched upon many of her core progressive positions – including critiques of Wall Street and the decline of incomes and economic opportunity for the American middle class – was able to skirt into the building without facing the crowd of protesters.

During her speech, however, one of the protesters standing in the very back of the room could be seen consistently holding up a "Bernie" sign.

Warren, whose speech reiterated many similar positions to Sanders, still vowed to fight for the American middle class and to "get money out of politics."