Rep. Tom Marino (R-Pa.) testifies during a House Human Resources Subcommittee on Capitol Hill, May 18, 2016 in Washington. (Mark Wilson/Getty Images)

One of President Trump’s biggest supporters on Capitol Hill is preparing to serve as the next White House drug czar, according to published reports.

Rep. Tom Marino (R-Pa.), who represents Pennsylvania’s rural 10th Congressional District, is in the final stages of the paperwork process to be nominated to lead the Office of National Drug Control Policy, according to CBS News.

A Marino spokeswoman didn’t immediately return requests for comment.

Marino, 64, was among Trump’s earliest backers and took on an increasingly visible role over the course of the presidential campaign. He campaigned with Trump across Pennsylvania — a state Republicans won for the first time since 1988 — and was awarded by the campaign with various chits, including a seat in the coveted VIP box during the Republican National Convention.

But on Capitol Hill, Marino is known for his work on drug-control matters. A former federal prosecutor from Williamsport, Pa., his Transnational Drug Trafficking Act became law as did legislation that critics say undercuts the Drug Enforcement Agency’s ability to hold drug distributors accountable.

The Ensuring Patient Access and Effective Drug Enforcement Act was supported by large drug distribution companies and their professional association. Passed in 2016, the bill raises DEA standards to stop the distribution of prescription drugs if they believe there’s a threat to the general public. Critics say the new law sets a nearly impossible burden to meet against distributors and that the new law essentially protects distributors from having their drugs locked up with little notice.

The head of ONDCP, commonly known as the “drug czar,” requires Senate confirmation. If confirmed, Marino would be the fifth congressional Republican tapped to serve in the Trump administration, joining former Reps. Tom Price of Georgia (now serving as Health and Human Services secretary), Mick Mulvaney of South Carolina (director of the Office of Management and Budget), Mike Pompeo of Kansas (CIA director) and Ryan Zinke of Montana (Interior secretary).

A special election to succeed Pompeo is being held Tuesday, while the election to succeed Price is next Tuesday.

If historic trends hold, the race to succeed Marino should keep the seat safely in Republican hands. He won reelection last November with slightly more than 70 percent of the vote. Trump won all of the counties in the district with at least 60 percent of the vote.