Trump’s tight grip on the GOP has upended his party’s nomination fights, while Democratic members of Congress are navigating generational divides and redistricting.

Sen. John Cornyn is just the latest high-profile Republican incumbent to learn that in today’s GOP, conservative credentials are no match for Trump’s grip on the party.

President Trump's strong influence in Republican primaries presents a challenge for the party's upcoming midterm elections. Voters are reportedly unhappy with his economic…