Donald Trump has introduced a new element of concern into relations with Russia and China: the nuclear factor. In a confusing message on social media, just minutes before beginning his meeting this Thursday in South Korea with Chinese President Xi Jinping to discuss trade, the US leader announced that he has ordered the Pentagon to conduct nuclear weapons tests “immediately.” These would be the first since 1992.

“Since other countries have testing programs, I have instructed the War Department [Pentagon] to begin testing our nuclear weapons like they do. This process will begin immediately,” Trump writes.

The message, although it does not mention any specific country, comes hours after Russian President Vladimir Putin confirmed on Wednesday that the Kremlin has successfully tested a nuclear-powered super torpedo, the Poseidon, capable of unleashing huge radioactive tsunamis that could annihilate large coastal areas.

Trump has not made it clear whether he is referring to nuclear warhead tests, which could destabilize decades-long efforts against weapons proliferation, or whether he is simply referring to the delivery systems and missiles used to transport them without a nuclear payload. Adding to the confusion is Trump's reference to the Pentagon as the agency that received the order, even though the Department of Energy is responsible for conducting nuclear tests.

“The United States has more nuclear weapons than any other country,” the US president emphasized in his message, noting that Russia is the second country and China the third, “far behind, although it will equal it in the next five years.”

The Federation of American Scientists (FAS) estimates that Washington possesses approximately 5,200 nuclear warheads, while Russia has around 5,450, including deployed, stored, and decommissioned warheads in both cases. China has doubled its arsenal since 2020, increasing from 300 to 600 warheads by 2025, and the Department of Defense estimates that by 2030 it will have surpassed 1,000.

Trump's announcement came moments before his landing in South Korea, where he met with Chinese President Xi Jinping on Thursday. When asked by reporters about the order he had just issued, the US president declined to comment during the summit. Upon his return to Washington aboard Air Force One, he did address the resumption of nuclear testing:"We stopped them many years ago, but since others are doing them, I think it's appropriate that we do them as well." He indicated that details of these future tests would be released later.

Tension with Russia

The test launches, from a submarine, of the Russian Poseidon super torpedo —a projectile about 24 meters long capable of carrying a nuclear warhead and operating in part as an underwater drone— have taken place in a context where the relationship between Trump and Putin appears to be deteriorating, after the American announced the cancellation of a bilateral summit in Budapest due to the Russian's resistance to sitting down to negotiate peace in Ukraine.

The existence of the Poseidon missile was announced by Putin back in March 2018. On October 21, Russia also conducted tests of the new Burevestnik cruise missile, but so far has refrained from carrying out nuclear detonations.

The United States conducted its last nuclear weapons test on September 23, 1992, at the end of the Cold War, at its National Security Center in Nevada. Since then, it has observed a voluntary moratorium on underground explosions.

The purpose of such a test, at least theoretically, is to verify the proper functioning of a prototype or to ensure that older weapons that have been in storage for some time still retain their effectiveness. But it can also represent a way to flex military muscle against rival countries.

The moratorium in place for three decades has been one of the pillars of nuclear non-proliferation, but Trump's order could blow up those efforts.

Proponents of nuclear arms control immediately began criticizing Trump's announcement. In a message on the social media platform X, Daryl Kimball, executive director of the Arms Control Association in Washington, stated: “Trump is misinformed. The United States has no political, technical, or military grounds to resume exclusive nuclear testing for the first time since 1992.”

Also in X, Democratic Senator Ed Markey opined: “The United States has not conducted a nuclear test since 1992 and should not resume them. This is a reckless decision that will leave us less safe and lead to a new nuclear arms race.”