Phil Washington, the CEO of Denver International Airport and embattled nominee to become the next FAA Administrator, has withdrawn from consideration, U.S. Transportation Secretary Pete Buttigieg confirmed on Saturday evening. Buttigieg released a statement on Twitter saying, “The FAA needs a confirmed Administrator, and Phil Washington’s transportation and military experience made him an excellent nominee. The partisan attacks and procedural obstruction he has faced are undeserved but I respect his decision to withdraw and am grateful for his service.”

The White House initially nominated Washington to the post in July. At the time, he had been CEO of the airport for six months but brought years of transportation experience as the CEO of the Los Angeles County Metropolitan Transportation Authority and of the Denver Regional Transportation District. He also spent 24 years in the U.S. Army and led Biden’s transportation transition team after he won the presidential election.

However, Republicans in both the Senate and the House raised objections over his experience, saying the FAA is facing numerous challenges that required a person with a strong aviation background. Sen. Ted Cruz (R-Texas), the ranking Republican on the Senate Commerce Committee, led the objections calling him the wrong person for the job.

Also clouding the nomination was a corruption probe ongoing stemming from Washington’s time as CEO of the Los Angeles County Metropolitan Transportation Authority. The California Attorney General’s office confirmed to Cruz that Washington was a “material” part of this probe.

While the Biden Administration initially nominated Washington in July, the Senate failed to act on it before that previous Congress concluded, oftentimes a sign that a nomination would whither away. Biden, however, resurrected the nomination in January when the new Congress took office.

Following the recent notam system meltdown and aircraft close calls that were making headlines, Senate Majority Leader Chuck Schumer (D-New York) called for action, saying: “It’s time to clear the runway for President Biden’s choice for FAA Administrator, Phil Washington.”

Senate Commerce Committee Chair Maria Cantwell (D-Washington) offered strong support citing his background in transportation and her office released numerous letters of endorsement from unions, airport groups, airlines, and from past FAA administrators—who like Washington had limited aviation experience when they stepped into the role of leading the agency.

While the Commerce Committee held a hearing in February and scheduled a vote on the nomination this past Wednesday, signs of trouble of its ultimate fate arose when Cantwell delayed that consideration at the last minute, saying there would be a “future date pending information that members have been seeking.” While she did not elaborate on what information or which members were seeking it, she also stressed, “We will have this debate in the future.”

However, it had become unclear whether the votes were present to push through the nomination. In addition to Republican opposition, Senate Commerce Committee members Kyrsten Sinema (I-Arizona) and Jon Tester (D-Montana) reportedly appeared uncertain on the nomination.

Alongside the opposition in the Senate, the nomination was receiving objections in the House. House Transportation and Infrastructure Committee Chair Sam Graves (R-Missouri) had said Washington required a waiver from a provision requiring that the FAA Administrator be a civilian. Graves suggested the House would not provide such a waiver.

Meanwhile, Cruz has offered acting Administrator Billy Nolen as an alternative nominee saying such a prospect would have a “clear and easy path” to confirmation with bipartisan support.