Dozens of Republican convention delegates are hatching a new plan to block Donald Trump at this summer’s party meetings, in what has become the most organized effort so far to stop the businessman from becoming the GOP nominee.

The delegates are angered by Trump’s recent comments on gun control, his racial attacks on a federal judge and his sinking poll numbers. They are convinced that Trump is an insufficiently conservative candidate and believe they will find enough like-minded Republicans within the next month to change party rules and allow delegates to vote for whomever they want, regardless of who won their state caucus or primary.

The new campaign is being run by the only people who can actually make changes to party rules, rather than by pundits and media figures who have been pining for a Trump alternative. Many involved in the delegate-driven movement supported Sen. Ted Cruz of Texas in the primary but say they have no specific candidate in mind and are not taking cues from any of Trump’s vanquished opponents.

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