Kasich has not thrown his support to Donald Trump, who became the presumptive nominee in early May after he and Sen. Ted Cruz left the race.
Kasich believes holding onto his delegates is a smart play in a campaign season that has been wild and unpredictable, an aide explained. The governor also thinks his delegates could become leverage to encourage Trump to be a more positive and unifying figure ahead of the Republican National Convention in Cleveland, said the aide, who requested anonymity to speak candidly.
Sens. Cruz of Texas and Marco Rubio of Florida, who also accumulated delegates before suspending their candidacies, have issued similar directives asking that their delegates remain bound.
Kasich's message to party officials in the letters, dated Monday and signed by the governor, was brief. In one such correspondence, Kasich wrote to Ohio Republican Party Chairman Matt Borges, "I appreciate the work of the party during this primary season, and I thank the voters of Ohio for putting their faith in me. Although I have suspended by campaign, I do not release any Delegates bound to me."
Kasich sent similar messages to the party chairmen in the District, Illinois, Iowa, Kansas, Kentucky, Maine, Massachusetts, Michigan, New Hampshire, New York, Nevada, North Carolina, Rhode Island, Vermont, Virginia and West Virginia. He copied Republican National Committee Chairman Reince Priebus and RNC General Counsel John Ryder on each letter.