Ronny Jackson, former White House doctor and Trump VA nominee, running for Texas congressional seat
FILE PHOTO: U.S. President Donald Trump's nominee to be U.S. Secretary of Veterans Affairs, Navy Rear Adm. Ronny Jackson, meets with Senator Jon Tester (D-MT) at his office on Capitol Hill in Washington, U.S., April 17, 2018. REUTERS/Joshua Roberts

Jackson is at least the 13th Republican to jump into the race to replace retiring U.S. Rep. Mac Thornberry, R-Clarendon.

Ronny Jackson, the former White House doctor and President Donald Trump's onetime nominee to be secretary of veterans affairs, is running to replace retiring U.S. Rep. Mac Thornberry, R-Clarendon.

With hours until the filing deadline, Jackson, a former Navy rear admiral, arrived at the Texas GOP headquarters in Austin on Monday afternoon to submit paperwork for the seat.

Trump nominated Jackson last year to lead the Department of Veterans Affairs, but he withdrew from consideration amid allegations of professional misconduct, including drinking on the job and overprescribing medication. He called the accusations "completely false and fabricated."

After the nomination debacle, Jackson continued to work for the White House medical unit but not as the president's personal doctor. Jackson previously served as physician to Trump's predecessor, Barack Obama.

Jackson retired from the Navy earlier this month, according to CNN, which said the retirement came even as the Defense Department's inspector general was still probing the allegations against him.

Former Navy Read Adm. Ronny Jackson fills out paperwork for his campaign to replace retiring U.S. Rep. Mac Thornberry, R-Clarendon.

Jackson is a native of Levelland, a city about a half-hour west of Lubbock — and outside Thornberry's 13th District. The law does not require congressional candidates to live in the district, but after word got out last month about Jackson's interest in the race, Thornberry issued a statement making clear he was not pleased with "outside candidates" circling the seat.

Jackson is at least the 13th candidate to enter the Republican primary for the ruby-red seat, joining others including Chris Ekstrom, a prominent GOP donor and businessman from Dallas; Elaine Hays, a member of the Amarillo City Council; and Josh Winegarner, director of industry affairs for the Texas Cattle Feeders Association. Democrat Greg Sagan, who challenged Thornberry last year, is also running in 2020.

Ekstrom's campaign seized on Jackson's connection to the former Democratic president in response to his filing, issuing a statement welcoming "President Obama's Doctor Ronny Jackson" to the race and noting Obama's past praise for Jackson.

"The Obama Administration was a disastrous eight year period that destroyed the middle class, attacked traditional conservative values at every turn, and opened our borders to dangerous criminals and cartels," the statement said. "We welcome a spirited debate about which candidate will best represent the conservative values of Texas 13 in the weeks ahead."