Kansas delegates are particularly key: They are required to remain with whomever they are pledged to until the candidate officially releases them — unlike most states, they are not allowed to vote their conscience unless explicitly given permission, which Cruz isn’t giving them.

“Although I have suspended my campaign for the Republican Party nomination for President of the United States, I do not release any Republican National Convention delegates bound to me as a result of the 2016 delegate selection process that took place in your state,” Cruz wrote in a letter to Kelly Arnold, the chair of the Kansas GOP and obtained by CNN.

Oklahoma’s Republican Party received a similar letter from the Cruz campaign, state GOP chair Pam Pollard told CNN. As did the Texas GOP, according to executive director Kyle Whatley.