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After Bernie Sanders doubled down on his endorsement of Hillary Clinton Monday, many of his supporters remain politically homeless and in no mood to back the presumptive Democratic nominee  -- a situation Donald Trump is keen to exploit.

His campaign and allied Republicans are now launching a renewed push to bring the loyal opposition from the Democratic primary race aboard the Trump train.

“They’re liking what I’m saying in terms of trade,” Trump told Fox News' "Hannity" on Tuesday, after making an open appeal to Sanders supporters in his convention speech last week. “I think we’re going to get a lot of [Sanders] supporters.”

Conversations with Sanders supporters in Philadelphia suggest a number of them are now resolved to oppose Clinton in November, following the scandal over leaked DNC emails that indicated a pro-Clinton bias at the top during the primary campaign.

Trump surely would have a tough time winning them over in large numbers -- but some in the "Never Hillary" camp indicated a willingness to consider voting for him.

“I think it would be a disaster if [Hillary Clinton] was elected,” Jared Foster, a combat veteran from Joanna, S.C., told FoxNews.com. He said he wants to support Sanders, but would support Donald Trump presuming Clinton formally claims the nomination this week.

The signs and chants in street protests outside the Democrats' convention in Philadelphia made plain the sentiments of the Sanders crowd.

“Hell no DNC, we won’t vote for Hillary” and “lock her up” were repeatedly chanted during Monday’s pro-Sanders march. Some signs portrayed Clinton as a war criminal, while another presented her as Shakespearean antagonist Lady Macbeth.

Tracy Graunstadt, who had traveled from Michigan to protest, was holding a sign that said “You can’t make me vote for Hillary” and told FoxNews.com the leaked DNC emails were the tipping point for her.

“That was the final straw for me. I was a little bit on the fence before ... but after seeing how the DNC essentially rigged the election and worked against Bernie, and I think that Hillary knew exactly what was going on,” she said. “I could never vote for someone like that.”

“For my own conscience, I will not be able to do something I don’t believe in,” agreed Alex Ozkaynak, a Brooklyn resident.

Trump is not their only option. Many protesters eyed Green Party candidate Jill Stein as their anti-Clinton choice, sporting green flags and Stein placards.

Yet some showed themselves open to the unlikely possibility of voting for Trump as an alternative, even just as a way to knife Clinton after what many perceive as a stolen primary process.

While the most likely positive outcome for the Trump campaign is that Sanders supporters stay home or vote for Stein, shaving off vital percentage points from Clinton in swing states like Pennsylvania and Michigan could make a difference.

"I'll bet you a lot of his people come to us," Trump said Monday in Roanoke, Va., again citing their common cause on trade.

After Sanders’ speech Monday backing Clinton, though, Trump accused Sanders of abandoning his revolution. “We welcome all voters who want to fix our rigged system and bring back our jobs,” he said.

Another tweet presented the billionaire as the post-Bernie candidate.

Though there is a gulf in the two candidates' views on subjects such as abortion, political correctness and especially immigration, there are also similarities. Both campaigns have appealed to voters as movements that come from outside the Washington system, and have resonated with working class voters on issues like free trade.

Republicans hammered those similarities at their convention last week.

“What Bernie Sanders and Trump have in common, which is not a lot, is their appeal to the everyday working man and woman, and to the everyday American,” Keith Grover, a Utah state GOP representative, told FoxNews.com in Cleveland.

Sanders and Trump also have criticized Clinton using similar themes, namely her ties to Wall Street, allegations of corruption, and her stance on trade.

“Clinton betrayed Bernie voters. Kaine supports TPP, is in pocket of Wall Street, and backed Iraq,” Trump tweeted.

While Trump is unlikely to attract die-hard left-wing voters, he may be able to peel off others attracted to Sanders as an outsider.

"If Bernie Sanders supporters were to be disenchanted with their nominee and throw support behind Donald Trump, you bet that's totally in play and we know that the margins will be very small come fall," Grover said.

FoxNews.com’s Barnini Chakraborty and Fox News' Leland Vittert contributed to this report.