The Trump campaign feels confident the president will again win the state in 2020, according to two advisers close to the White House, even as Democrats make inroads in the vast urban areas and among state-held offices. But he could see the slimmest margin of victory for a GOP presidential candidate in generations: In 2016, he won by 9 percentage points, while past Republican presidential candidates won by larger margins in previous elections, including Mitt Romney by more than 15 points in 2012.

For Republicans, the concern lies mostly with down-ballot races as well as party support among suburban and female voters, two groups that turned away from the party during the 2018 midterms.

“I expect President Trump to win Texas by 5 percentage points, not 9 points this time,” said Cal Jillson, a political scientist at Southern Methodist University. “There are long-term demographic changes taking place in the state that eat into Republican support. The major cities like Austin, Houston and Dallas are already leaning blue. Plus, his Republican coalition has been destabilized by his own actions and conduct.”