Rep. Kenny Marchant (R-Tex.) speaks on Capitol Hill on May 17, 2013. Marchant announced his retirement Monday. (Charles Dharapak/AP)

Republican Rep. Kenny Marchant said Monday he will not seek reelection to represent his Dallas-area district, leaving open a third Texas House seat heavily targeted by Democrats in 2020.

Marchant’s announcement comes days after Rep. Will Hurd (R-Tex.) announced he would not seek reelection in a sprawling border district and less than a month after Rep. Pete Olson (R-Tex.) declined to seek reelection in the Houston suburbs.

All three men won reelection in 2018 by five percentage points or less — in Hurd’s case, by only a few hundred votes.

“I am looking forward to finishing out my term and then returning to Texas to start a new chapter,” Marchant said in a statement that thanked his family, staff, colleagues and constituents but did not detail the reasons for his departure.

Marchant’s retirement, first reported by the New York Times, is the latest blow to GOP hopes of retaking the House in 2020. The GOP retirements — which also include lawmakers in solidly Republican districts such as Reps. K. Michael Conaway (Tex.), Rob Bishop (Utah) and Martha Roby (Ala.) — send a signal that incumbents are not optimistic about returning soon to the majority.

Overall, 12 House Republicans who were sworn into the 116th Congress in January will not return in 2021, compared with three House Democrats.

One of the 12, Tom Marino of Pennsylvania, has already resigned and been replaced by another Republican, Fred Keller, in a special election. Two are seeking higher office: Rep. Bradley Byrne (Ala.) is running for Senate, and Rep. Greg Gianforte (Mont.) is running for governor.

House Minority Leader Kevin McCarthy, speaking on Fox News on Sunday, cautioned observers not to “misread” the meaning of the retirements, suggesting that many were retiring because they were set to lose their top committee posts because of party rules.

While Conaway and Bishop lead committees, that is not true of the other nine retiring Republicans.

The Republican plan to regain seats rests on the expectation that, with President Trump on the ballot, GOP voters will turn out more heavily relative to Democrats than they did in 2018.

“There’s a very clear plan to win the majority, and it has not changed based upon retirements,” McCarthy said. “And there will be others who retire, and it will not change in that course either . . . When you look at where the map is currently today and where these districts naturally perform, Republicans will gain.”

Democrats had put Marchant on a retirement watch list shortly after the midterm elections, and after Olson, Conaway and Hurd made their retirement announcements, they declared a “Texodus” underway. At least three other incumbent Texas Republicans — Reps. John Carter, Michael McCaul and Chip Roy — are considered by nonpartisan House analysts to be vulnerable to Democratic challengers next year.

Marchant’s district, centered on Dallas-Fort Worth International Airport and comprising affluent suburbs between the two cities, is one of several Texas districts that has become steadily more diverse over the past decade. In 2012, GOP presidential candidate Mitt Romney won the 24th District by 22 points; four year later, Trump won it by only six points.

Last year, Marchant beat his Democratic opponent by three points after winning by 17 points in 2016, and it has been a top Democratic target ever since. A member of the tax-writing Ways and Means Committee, Marchant had built a formidable campaign war chest — raising $747,000 this year to build a $2.2 million bank account.

But several motivated Democratic challengers had already emerged — including attorney Crystal Fletcher and retired Air Force colonel Kim Olson, who have both already raised six-figure sums.