Non-nuclear weapons programs should be prepared to pay the bills for the nuclear programs, if it comes to that, Sen. Deb Fischer (R-Neb.), one of the biggest nuclear weapons stakeholders left on the Senate Armed Services Committee, said Monday.

“Nuclear deterrence is the number one mission of the Department of Defense,” Fischer said in an online forum hosted by the Washington-based think tank, the Heritage Foundation. “That means when you’re putting together a budget, it’s the first thing, it’s the first thing that goes in.”

It would be “backwards” to cut nuclear weapons to fund priorities such as a cyber or artificial intelligence, said Fischer, the ranking member of the Armed Services strategic forces subcommittee whose state includes both U.S. Strategic Command headquarters outside Omaha, Neb., and rural communities surrounding Minuteman III silos crewed by the Air Force’s 90th Missile Wing.

Fischer was pushing back against a common refrain of arms control and disarmament groups in Washington — grown louder since Democrats took control of the federal government in November — who say the $1-trillion, 30-year nuclear modernization regimen started by the Obama administration in 2016 will squeeze out funding for more urgent conventional weapons programs.

The modernization program includes both the civilian nuclear weapons budget at the Department of Energy’s National Nuclear Security Administration (NNSA), which refurbishes nuclear warheads and bombs, and Pentagon acquisition of new missiles and new air- and sea-going carrier craft. The Congressional Budget Office has estimated nuclear modernization expenses will peak in the 2030s at around 7% of the total defense budget.

“We shouldn’t act like it’s no big deal,” Fischer said. “Nuclear modernization is not cheap, but it’s necessary.”

Fischer spoke with the Biden administration in the middle of closed-door reviews about nuclear weapons that has at various times since inauguration day kept high-level officials tight-lipped about whether procurements such as the Ground Based Strategic Deterrent, Minuteman III’s planned replacement and the NNSA’s two-state plutonium-pit production complex will go forward as planned under the modernization started by Obama and supplemented by Trump.

Nuclear modernization looks to figure into a hearing scheduled for Tuesday in the House Appropriations defense subcommittee, titled “Future Defense Spending.” Scheduled witness James Acton, a nuclear expert with the Carnegie Endowment for International Peace, has already posted advance testimony urging Congress to pause the Ground Based Strategic Deterrent program for review, abandon early studies into a planned nuclear-tipped sea-launched cruise missile and boost funding for nuclear command and control upgrades.