Cheney accepts Pelosi’s appointment to the Jan. 6 committee, angering McCarthy.

Speaker Nancy Pelosi on Thursday named Representative Liz Cheney, Republican of Wyoming and a harsh critic of former President Donald J. Trump, to a newly created special committee to investigate the Jan. 6 riot at the Capitol, taking the unusual step of giving one of her seats to a member of the opposing party.

Ms. Cheney was ousted from her Republican leadership post for speaking out about the role that Mr. Trump and her own party played in pushing false claims of voting fraud that stoked the riot, which unfolded as...