Gov. Mike Dunleavy said his administration will no longer respond to or participate in hearings led by Sen. Lora Reinbold, telling the fellow Republican in a withering letter Feb. 18 that she has used her position to “misrepresent” the state’s COVID-19 response and that her demands for information are “not based in fact.”

Reinbold has criticized the governor’s pandemic disaster declarations and taken aim at health restrictions imposed by local governments, airlines and the Legislature, including mask requirements. She has used social media to question medical science and accuse the Dunleavy ad...