Phelan M. Ebenhack/AP
- New Hampshire Gov. Chris Sununu on Sunday told NBC News that he will support the 2024 nominee.
- But Sununu, a potential presidential contender, predicted Donald Trump won't be the 2024 GOP nominee.
- RNC leadership said GOP candidates must sign a pledge to support the nominee to participate in debates.
New Hampshire Gov. Chris Sununu said he plans to support the Republican presidential nominee in the 2024 election, but he doesn't believe it's going to be former President Donald Trump.