Trump Moves “Nuclear” Subs: Negotiating Tactic or Escalatory Gamble?

Q2: Are these nuclear-powered submarines or nuclear-armed submarines?

A2: The difference is crucial because of the great difference between nuclear-powered submarines (their propulsion) and nuclear-armed submarines (their weapons). Unfortunately, confusion has arisen because President Trump called these “nuclear” submarines without any additional information—likely intentionally to preserve operational security.

All U.S. submarines are nuclear-powered. Only 14—the ballistic missile submarines (SSBNs, or “boomers”) —carry nuclear weapons. In the past, U.S. attack submarines had nuclear weapons, but these were removed in the 1990s.

Russian attack submarines can carry nuclear weapons in addition to their conventional weapons. Thus, they are considered “dual-capable.” Russia and China have many conventionally powered submarines, though these typically have advanced propulsion and weapons technologies. The U.S. Navy retired its last conventionally powered submarine in 1990.

A nuclear-powered submarine does not, therefore, threaten Armageddon. That threat comes from the weapons aboard the submarine, regardless of how that submarine is propelled through the water.

The chart below shows U.S. submarines, with those of Russia and China for context.

Q3: What does it mean to “position” a submarine?

A3: In this context, it means relocating a submarine that was already deployed. Day-to-day, the United States has about a dozen submarines deployed globally on various missions. There were no reports about unexpected submarine sailings, meaning there are no additional submarines at sea.

The short two-day interval between Trump’s order and the subsequent announcement that the submarines were on station means the submarines were already in Europe or the Western Pacific. U.S. submarines are capable of sustained submerged speeds of around 25 knots but typically move at a tactical speed of about 12 knots to maintain stealth. In 48 hours, they could travel 600–1,200 miles. That is enough time to move around in the theater, but not enough to sail from the United States or its territories.

Q4: Has the United States done this before?

A4: The United States frequently moves military forces, including nuclear-capable forces, to send political messages, but using submarines is unusual.

Visits by U.S. aircraft carriers and other large surface ships in allied ports are common to replenish supplies, facilitate professional exchanges, and illustrate military partnerships. Bombers, too, have been employed to represent the global reach of the U.S. military power. For example, in April, the Trump administration moved B-2 stealth bombers to Diego Garcia as the president warned of further action against Iran and its proxies. B-52 bombers flew over Estonia, around 50 miles from the Russian border, earlier this year to mark Estonian independence day. The Biden administration deployed Bomber Task Forces 33 times in 2024 alone, including to Sweden and Finland on Russia’s periphery.

Both the B-2 and B-52 can deliver nuclear weapons, while U.S. carriers are nuclear-powered, so using a “nuclear” asset on its own is not exceptional. Trump’s order was unusual because U.S. submarine movements and positions are rarely discussed publicly, given the Navy’s emphasis on operating covertly. For that reason, the president’s announcements have been vague and, as a result, of little intelligence value to the Russian military.

Q5: Which submarines were likely repositioned?

A5: These were almost certainly nuclear-powered attack submarines, which no longer have nuclear weapons.

There is no need to reposition ballistic missile submarines because of their long range. Their Trident II missile has a range of 7,400 miles. That means that they can reach targets in Russia from anywhere in the Atlantic. A U.S. ballistic missile submarine at its home port of Kings Bay, Georgia, can hit Moscow in less than half an hour.

Further, using these submarines for signaling would undermine their primary mission to remain hidden. The one recent exception was during the Biden administration, when an SSBN made a port call in Busan as an exceptional step to reassure South Korea of the U.S. security commitment.

Attack submarines are not threatening because of nuclear weapons, which they lack, but because of their ability to strike surface ships and, particularly, submarines. The submarine versus submarine competition was intense during the Cold War and has revived as Russia has become more aggressive and anti-Western. Russia has also kept its submarine fleet relatively modern, unlike its surface fleet, which has languished.

The U.S. attack submarines might have moved into the Norwegian Sea, close to the Russian northern submarine bases at Murmansk and the Kola Peninsula. A submarine in the Pacific might have moved near the main Russian naval base at Vladivostok or the submarine facilities at Avacha Bay.

It’s possible that one of the submarines was a cruise missile submarine (SSGN). The United States has four of these, converted from SSBNs, and one, the USS Ohio, is at sea in the Pacific. Their 154 conventionally armed cruise missiles are designed to strike land targets. One of these submarines launched Tomahawk missiles at the Iranian nuclear facilities in Esfahan during “Operation Midnight Hammer.” Tomahawk missiles have a long range (900 miles), but by getting closer to Russian territory, these submarines could strike more targets.

Q6: Why did President Trump do this?

A6: There are two likely reasons: negotiations over Ukraine and push back against Russian nuclear saber-rattling.

Russian refusal to negotiate a settlement for the Ukraine war has frustrated President Trump, and he has repeatedly criticized Putin for Russia's intransigence. President Trump has stopped his criticisms of President Zelensky and even authorized the Europeans to buy U.S. weapons to arm Ukraine. Steven Witkoff, Trump’s special envoy for Ukraine, will be in Moscow this week for discussions about moving the negotiations ahead, and this move may have been intended to strengthen his hand.

President Trump also appears to be signaling his annoyance at Russian nuclear saber-rattling. President Putin has done this several times in the past three years. He has, for example, ordered nuclear forces to a heightened alert status, fiddled with the nuclear doctrine, and issued veiled threats, including warnings of consequences “such as you have never seen in your history.” Although this recent threat did not come from an official government source, it mirrored the previous threats.

The Biden administration had been cautious in responding to Russia’s saber-rattling, fearing escalation, and had been criticized for appearing to be intimidated. Trump is willing to take a tougher and slightly riskier approach.

The bottom line: President Trump's action does not change the nuclear balance or bring conflict closer. Of the options available, moving a “nuclear” submarine was probably the least provocative step possible while still making a political and diplomatic statement. Raising nuclear alerts or moving nuclear weapons forward would have been far more escalatory.

Russian rhetoric, save for Medvedev, has been muted so far. Thus, this mini-crisis will likely fade away as the parties focus on negotiations. However, more threatening language from official or semiofficial Russian sources could engender another U.S. response.

Mark F. Cancian (Colonel, U.S. Marine Corps Reserve, ret.) is a senior adviser with the Defense and Security Department at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Chris H. Park is a research associate for the Arleigh A. Burke Chair at CSIS.