Adam Kinzinger’s Lonely Mission

WASHINGTON — As the Republican Party censures, condemns and seeks to purge leaders who aren’t in lock step with Donald J. Trump, Adam Kinzinger, the six-term Illinois congressman, stands as enemy No. 1 — unwelcome not just in his party but also in his own family, some of whom recently disowned him.

Two days after Mr. Kinzinger called for removing Mr. Trump from office following the Jan. 6 riot at the Capitol, 11 members of his family sent him a handwritten two-page letter, saying he was in cahoots with “the...