Delegates Unbound is hoping to convince the GOP not to nominate Trump.
McConnell said Trump has made "a number of very significant gaffes."
The plan would let GOP convention delegates vote their "conscience" for any candidate.
Peter Schroeder 06/24/16 01:07 PM EDT
Trump is "rooting for the economic turmoil," a Clinton aide says.
"If Hillary Clinton came to me ... I would say yes," the senator said.
"I think that there are a lot of lessons learned all around," Michael Caputo said.
Sanders gave three conditions Clinton could meet for getting his endorsement.
Clinton called for unity in the face of "economic uncertainty."
"It's so crazy we have to argue about sane gun control legislation," he said.
Timothy Cama 06/24/16 09:45 AM EDT
Donald Trump Jr. defended regulations on oil and natural gas drilling on federal land.