FILE PHOTO: House Armed Services Committee Chsirman Mac Thornberry (R-CA) chairs a committee hearing on "The National Defense Strategy and the Nuclear Posture Review" on Capitol Hill in Washington, U.S., February 6, 2018. REUTERS/Joshua Roberts

WASHINGTON (Reuters) - The top Republican on the U.S. House Armed Services Committee, Representative Mac Thornberry, said on Monday he will not run for re-election to the House of Representatives next year, adding to the long list of high-profile members of his party leaving Congress.

Thornberry, who chaired the powerful committee from 2015 to the start of this year, said in a statement he felt it was time for a change after 25 years in Washington. His district in Texas’s northern panhandle is one of the most reliably Republican in the United States, having gone 80 percent for Trump in 2016.

Democrats took control of the House in January, after sweeping victories in the November 2018 U.S. elections. Nineteen Republican House members have either left or announced plans to step aside rather than seek re-election in 2020.

Thornberry has generally backed Republican President Donald Trump’s policies, but he did question the president’s decision to take money from the military budget to pay for a wall on the border with Mexico.

In March, Thornberry said he supported building the wall, but not by shifting money meant for defense for non-defense purposes.

As Armed Services chairman, Thornberry helped win large increases in U.S. military spending; the Pentagon’s annual budget is now over $700 billion. He also worked to streamline the Pentagon’s outdated acquisitions system.

Among other House Republicans from Texas departing from Congress are Representative Mike Conaway, the top Republican on the agriculture committee, and Will Hurd, the chamber’s only African-American Republican.

Under Republican term-limits rules, Thornberry would have had to leave his position as the top Armed Services Republican in 2021.