Representative Kenny Marchant of Texas is planning to announce his retirement on Monday, according to two Republican officials, becoming the fourth Republican House member from Texas in recent weeks to head for the exits rather than face re-election in 2020 in a state that is rapidly becoming more competitive.
Mr. Marchant, who was first elected in 2004, won his suburban Dallas district by comfortable margins for over a decade, but last year he prevailed by only three points against a Democratic opponent who had relatively modest financial resources. Mr. Marchant, a low-key member and reliably conservative vote, sits on the influential Ways and Means Committee.
With Mr. Marchant, a total of 11 House Republicans plan to retire or seek another office in 2020; just three House Democrats have announced they won’t run again. The Democrats hold a 37-seat majority in the House with two vacancies at the moment.
After a generation of dominance in Texas, Republicans are now facing the same challenges as their counterparts in other parts of the country: By linking themselves to President Trump and his incendiary brand of nationalist politics, they are alienating the sort of suburban voters who were once among the Republican Party’s most dependable supporters.
This realignment, combined with Texas’s increasing diversity, propelled two freshman Democrats, Representatives Colin Allred and Lizzie Fletcher, to victory last year in districts anchored around Dallas and Houston.
And such political shifts are giving Democrats hope that they can make even more gains next year, when Mr. Trump will be on top of the ticket. Their prospects have gotten a considerable lift in the past two weeks as Representatives Pete Olson, Will Hurd and K. Michael Conaway, all Texas Republicans, have announced their retirements.
While Mr. Conaway’s district is heavily conservative, Mr. Hurd and Mr. Olson represent districts that are full of nonwhite voters and that Republicans will struggle to defend. The loss of Mr. Hurd was an especially stinging blow because he is the only black Republican in the House.
The same demographic forces were also looming for Mr. Marchant, whose district sprawls to the northwest of Dallas. After winning re-election by 33 percentage points in 2014, his margin of victory fell to 17 percentage points in 2016 and then plunged to just three points last year. Similarly, while Mitt Romney won the district by 22 points, Mr. Trump carried it by only six points in 2016.
While the president is still favored to win in Texas in 2020, his unpopularity with college-educated voters could make the state more competitive than it has been for decades. In addition to the three competitive Texas seats held by the House Republicans who are retiring, Representatives John Carter, Mike McCaul and Chip Roy could also face hard-fought races.