WASHINGTON: US Republicans have taken to social media in droves to burn their voter registration cards, renounce their political affiliation, and pledge never to vote for their party’s presumptive nominee Donald Trump in November. Trump is basking in the glory of an all-but-certain victory in the chaotic GOP nomination race, after rivals Ted Cruz and John Kasich raised their white flags of surrender. But Trump’s rise presents a moment of truth for Republicans: can they rally around one of the most contentious presidential nominees in modern history? Astounding displays of antagonism are coming from conservatives who under more normal circumstances would likely be backing the Republican standard-bearer. Startling images landed on Twitter Tuesday and Wednesday in the hours after the braggadocious billionaire’s sweeping Indiana primary victory, including a shot of conservative writer Lachlan Markay and video of one Bryan Akner, both setting their voter registration cards alight. One of the chief challenges on Trump’s hands as he shifts from the nominations battle to a likely general election brawl against Democrat Hillary Clinton is how to win over Republicans infuriated by his candidacy.