After leaving Texas for Illinois to prevent a legislative vote on a Republican redistricting plan, state House Democratic leader Gene Wu needed a means to project his voice — and viewpoints — to a national audience. So he tapped his campaign account to buy a microphone for news conferences.

The FBI will help Texas track down Democratic state lawmakers who left the state as part of a collective effort to thwart state Republican efforts to redraw congressional districts, Republican U.S. Senator John Cornyn said on Thursday.