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.