China’s 119 nuclear, intercontinental ballistic missile silo construction sites.

China’s 119 nuclear, intercontinental ballistic missile silo construction sites.

Photo: Planet Labs Inc./James Martin Center for Nonproliferation Studies

New satellite images published recently reveal that China is building more than 100 new nuclear missile silos in its western desert. Many American arms-control proponents, including the researchers who made the discovery and the Washington Post editorial board, immediately blamed China’s actions on U.S. nuclear modernization plans and recommended that Washington make an arms-control deal with China to address this nuclear threat. This is both the wrong diagnosis and the wrong solution.

China is engaging in a massive nuclear-arms buildup as part of its broader strategy to challenge the U.S.-led rules-based international system, and the U.S. will need to respond by updating its nuclear program to defend itself and the free world.

For decades, China possessed a modest nuclear arsenal of a few hundred weapons. Unlike the U.S. and the Soviet Union, China never built a large nuclear arsenal during the Cold War, because the country’s nuclear doctrine promised never to use nuclear weapons first and called for a minimal force capable of retaliating against enemy attack.

U.S. defense strategists, however, long feared that China would eventually try to compete with the U.S. nuclear arsenal. They believed that as China became a geopolitical superpower, its leaders would eventually pursue a superpower nuclear arsenal.

That is exactly what we are seeing today. The new missile silos in the desert are part of a Chinese nuclear buildup that includes new submarines, bombers, and ballistic and hypersonic missiles. U.S. defense officials, including Commander of U.S. Strategic Command Charles A. Richard, have publicly testified that China’s nuclear arsenal will double, if not triple or quadruple, within the decade. This buildup could make China a nuclear peer with the U.S. and Russia, which each maintain no more than 1,550 strategic nuclear weapons, per New Start Treaty limits.

China’s buildup threatens all major U.S. defense and deterrence goals. It makes it harder for the Pentagon to deter Chinese strategic attacks and coercion and to maintain a favorable balance of power and assure allies in the Indo-Pacific.

This means that for the first time in history, the U.S. will have to contend with two adversaries with substantial nuclear arsenals. Sizing the U.S. nuclear force for parity with Russia and treating China as a lesser power will no longer work.

The arms-control proponents say we should not panic and that these new silos are meant only to ensure that China’s nuclear weapons can survive a U.S. nuclear first strike. They say the solution is arms-control talks with Beijing.

This doesn’t make sense. The U.S. has drastically cut the size of its nuclear arsenal since the end of the Cold War, and President Biden has promised to reduce the role of nuclear weapons in U.S. national-security policy. If Beijing were worried about a U.S. first strike, it would put nuclear weapons on mobile missiles and submarines, which are harder for the Pentagon to find and destroy. China’s new fixed silos, in contrast, are relatively easy targets, but they do improve China’s ability to threaten a first strike against its opponents.

Arms-control talks with China, attempted unsuccessfully during both the Obama and Trump administrations, are unlikely to work any better for Mr. Biden. China’s nuclear buildup is intended to undermine U.S. defenses in the Indo-Pacific, break America’s regional alliances, and project China as a superpower.

To counter this challenge, the U.S. will need to strengthen its nuclear arsenal. It should continue with the bipartisan plans to modernize U.S. nuclear weapons. In addition, the Pentagon should study whether it can meet its deterrence requirements with existing stockpile numbers, or whether an increase beyond New Start limits is necessary.

Arms control can be pursued, but we have to be realistic. China has no history of negotiating constraints on its nuclear forces and it is unlikely to start now, during a massive expansion of its program.

Since the end of World War II, America’s nuclear forces have been the backbone of the U.S. alliance system and the rules-based international system. China is building new nuclear forces to tear those systems down. By strengthening its arsenal, the U.S. can fend off China’s challenge and provide the free world with continued peace and stability.

Mr. Kroenig is a professor of government at Georgetown and the deputy director of the Atlantic Council’s Scowcroft Center. He served as a senior policy adviser for nuclear and missile-defense policy in the Office of the Secretary of Defense, 2017-21.

Main Street: If Joe Biden intends to outcompete Beijing, surely Milton Friedman still offers a more compelling model than simply copying the government-directed approach of Xi Jinping. Images: AP/Getty Images Composite: Mark Kelly The Wall Street Journal Interactive Edition