Democrat front-runner Hillary Clinton's campaign is trying to seize on the turmoil Donald Trump has caused within the Republican Party, hoping to gain the support of Republican voters and party leaders disillusioned by their standard-bearer.
The efforts come after House speaker Paul D Ryan, on Thursday said he was "just not ready" to back Trump, comments the Clinton campaign hailed on social media.
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At the same time, Priorities USA Action, a "super PAC (political action committee)" supporting Clinton, intends to reach out to Republican megadonors disillusioned by their party's presumptive nominee, The New York Times reported.
With the Democratic nomination in sight, Clinton has broadened her economic message, devoted days to apologising for a comment she previously made that angered working-class whites, and pledged that her husband, former president Bill Clinton, who remains widely popular among the blue-collar voters drawn to Trump, would "come out of retirement and be in charge" of creating jobs in places that have been particularly hard hit.
The campaign expects to assemble a "Republicans for Hillary" group, and Clinton has, from her days in the Senate and as secretary of state, cultivated strong relationships with prominent Republicans and their top staff members.
Mark Salter, a top adviser to Senator John McCain, this week expressed his support for Clinton on Twitter minutes after Trump clinched his party's nomination.
Clinton has also enjoyed a strong relationship with former defence secretary Robert M Gates, a Republican, who described her as "a superb representative of the US all over the world".
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On Friday, President Barack Obama helped in Clinton's effort. "Republican women, voters, are going to have to decide, 'Is that the guy I feel comfortable with representing me, and what I care about?'" he said of Trump at a news conference.
The Clinton campaign is also moving to exploit the public criticism of Trump by prominent Republicans.
On Wednesday, the campaign released an online ad that quoted Trump's former primary opponents describing him as a "know-nothing candidate", "a narcissist" and "the most vulgar person ever to aspire to the presidency", among other epithets.
However, Clinton's pitch to Republicans reflects the grim political realities of 2016, according to the CNN/ORC poll.
More than half of the registered voters who said they would vote for Clinton planned to do so in opposition to Trump, rather than in support of her candidacy, the poll said.