The Ground Based Strategic Deterrent program to replace nuclear-tipped Minuteman III intercontinental ballistic missiles should proceed as planned and the Biden administration’s nuclear posture review will be “unlike any that went before it” because of China’s rise on the world stage, the chair of the Senate Armed Forces strategic forces subcommittee said Tuesday.

Sen. Angus King (I-Maine), who caucuses with Democrats, made the remarks at a virtual forum hosted by the Center for Strategic and International Studies, a Washington-based think-tank.

King’s full-throated support was already evidenced by the Senate Armed Services Committee’s bipartisan National Defense Authorization Act, which authorized the Biden administration’s request to essentially continue the Trump administration’s proposed spending on upgrades for the U.S. nuclear arsenal, in line with the 30-year modernization plan the Obama administration started in 2016.

King said a recent visit to Minuteman III missile fields in North Dakota, and U.S. Strategic Command headquarters in Omaha, Neb., convinced him of the merits of not only retaining but refreshing the U.S. intercontinental ballistic missile (ICBM) fleet.

Disarmament advocates outside of government, and even some lawmakers who support a smaller nuclear arsenal, have broached the idea of eliminating, or at least shrinking, the ICBM fleet.

“What convinced me that that was a flawed strategy was that it really depends upon the theory of invulnerability of our submarines,” King said. “The nagging fear that I have and had is yes, the submarines are essentially undetectable now, but I don’t know how any of us can have confidence that that will continue to be the case five, 10, 15 years form now. We don’t know what’s going to be developed in terms of technology from space.”

King also said that the Biden administration will have its hands full with the nuclear posture review due in early 2022. The administration came into office touting the nuclear posture review as a means of exploring whether the U.S. could reduce the role of nuclear weapons in its defense strategy. King, on the other hand, said the review will have to include a hard look at new nuclear threats from Beijing.

“I don’t think we’ve ever had a more important nuclear posture review,” King said. “It’s going to be unlike any that went before it because we’re in the world of both China and … Russia, but also because we’re in a world of potential proliferation that is profoundly dangerous.”

Finally, King poured cold water on another idea that disarmament advocates have urged the Biden White House to explore: declaring that the United States will never conduct a nuclear first-strike.

“I’ve thought about no-first-use and it’s tempting to articulate that as a policy,” King said. But “part of deterrence is making your adversary nervous. You want your adversary to be a little unsure as to what the policy is going to be.”