Sen. Martin Heinrich (D-N.M.) will leave the Senate Armed Services Committee and join the chamber’s Appropriations Committee, keeping intact an important legislative shield for nuclear sites in the Land of Enchantment.

Sen. Charles Schumer (D-N.Y.) the majority leader, announced the committee assignments for the Democratic-controlled 117th Congress Tuesday on a call with the Senate’s Democratic caucus, Politico reported.

The changes leave New Mexico without a member on the Senate Armed Services Committee for the first time since 2015. Recently elected Sen. Ben Ray Lujan (D-N.M.), formerly the congressman for New Mexico’s 3rd legislative district, which contains the Los Alamos National Laboratory, will be on the Agriculture Committee, the Commerce Committee and the Health, Education, Labor and Pensions Committee.

In the 116th Congress, which ended Jan. 3 when the winners of the Nov. 3 elections were sworn in, New Mexico and its nuclear sites had Heinrich representing them on the Senate Armed Services Committee, and the now-retied Sen. Tom Udall (D-N.M.) representing them on the Appropriations Committee.

That means the state and its two nuclear weapons labs, Los Alamos in the north and Sandia, the engineering lab, in Albuquerque, will surrender their double-barreled advantage in the upper chamber, where Heinrich alone will be on watch for at least the next two years.

Heinrich, a largely pro-nuclear senator, had amassed some seniority on the Armed Services strategic forces subcommittee, which he was in line to chair, until he drew a new assignment. While on the Armed Services Committee, Heinrich seldom let either nominees for senior executive posts or bills slip by without making sure they would benefit nuclear programs in New Mexico.

The 49 year-old senator also went to bat for the Defense Nuclear Facilities Safety Board, the federal government’s independent watchdog for both active and shuttered defense nuclear weapon sites, except nuclear Navy sites. Heinrich, and other lawmakers, said the Trump administration tried to weaken the board’s oversight of the Department of Energy.

But most of all, Heinrich was unbending in his support to lock in plutonium pit production at the Los Alamos National Laboratory for the long term, even though some said the emphasis on factory production would fundamentally change the character of the nuclear weapons crucible, which once was called the Los Alamos Scientific Laboratory.

Over the last five years, Heinrich supported Los Alamos’ designation as the U.S. plutonium center of excellence and repeatedly badgered officials at the National Nuclear Security Administration (NNSA) about whether they really needed to make pits — fissile nuclear weapon cores — anywhere but at Los Alamos.

The NNSA plans to produce multiple war-usable pits at Los Alamos starting in 2024. By 2026, the lab would ramp up to 30 pits annually. By 2030, the NNSA wants to add 50 pits a year from the planned Savannah River Plutonium Processing Facility in Aiken, S.C., for a total of at least 80 pits annually. The agency needs the pits for future W87-1 warheads, which will top many of the 400 Ground Based Strategic Deterrent missiles the Air Force wants to deploy starting in 2030 or so to replace current Minuteman III missiles.