By just about every measure, Donald Trump’s sway with US voters has slipped since he won re-election two years ago, but there’s one place where his power remains unmatched: within the Republican party. The latest evidence of his ability to control who’s in and who’s out in the GOP came on Tuesday, when primary voters in Indiana ousted five of seven state senators who had last year defied the president’s demand to redraw the state’s congressional maps and gerrymander the state’s last two Democratic representatives out of their seats. True to form , Trump vowed revenge, and top Indiana Republicans such as senator Jim Banks together with outside groups aligned with the White House poured millions into unseating the seven dissidents. Only one survived Tuesday’s primaries, while another’s race is too close to call, according to the Associated Press.…