Since Russia’s unprovoked invasion of Ukraine began in February, nuclear weapons have catapulted back into the limelight, and tactical nuclear weapons have taken center stage. These weapons were designed during the Cold War to be a less powerful, battlefield alternative to their larger counterpart, strategic nuclear weapons—which can raze full cities. Russian President Vladimir Putin’s thinly-veiled threats to use nuclear weapons in Ukraine have caused nearly 70% of Americans to worry that his “special military operation” could result in nuclear war, yet many underestimate the danger of these weapons.

In fact, tactical nuclear weapons are, in our current political climate, arguably more dangerous than strategic nuclear weapons. Tactical nuclear weapons threaten to break the nuclear taboo that has been in place since the 1940s, meaning that their use could open the floodgates for all-out nuclear war. Since they’re considered a “less dangerous” option and are designed with battlefield strategy in mind, their purpose differs from that of strategic nukes, which is deterring a nuclear attack by an adversary. Their use could be more easily excused despite their capacity for destruction and the path they chart toward a global nuclear conflict.

Regardless of the misconception that they are relatively less dangerous, low-yield tactical nuclear weapons are still nuclear weapons, and as the saying goes, “you can’t un-ring a bell.” Once the use of nuclear weapons of any kind starts, there’s no way to predict how events will unfold. As author Fred Kaplan said in an interview with NPR, “nobody has the slightest idea what would happen after one nuclear weapon is used. Even if there is the finest tuned intention of keeping the war limited.”

Depending on where it is used, a singular detonation has the potential to kill hundreds of thousands of people and devastate the environment for centuries to come. Tactical nuclear weapons can range from 0.3 to 50 kilotons (one kiloton has the explosive force of 1,000 tons of TNT). Even the smallest nuke has 27 times the explosive power of the U.S. largest non-nuclear bomb, the MOAB, or about the same explosive power of the Beruit blast. And, these weapons can have a larger yield than the nuclear bombs dropped on Hiroshima and Nagasaki—which each killed tens of thousands upon impact and many others in subsequent years from radiation-caused cancers.

Any use of tactical nukes would also wreak havoc on the environment. From killing all living things, including plants and animals, within a huge radius to contaminating water with radiation that can last for billions of years, the existence of tactical nuclear weapons makes an apocalyptic future more tangible.

But, don’t we need more tactical nuclear weapons so we can compete with Russia? No. Though Russia has about 2,000 tactical nuclear weapons compared to the 230 of the United States, developing more would do little good. Tactical nuclear weapons don’t fit within our much-disputed doctrine of “mutually assured destruction” (MAD). The centerpiece of the doctrine posits that any offensive use of a nuclear weapon against another state would be met with an overwhelming nuclear counterattack. This assumption simply doesn’t consider the impact of low-yield tactical nuclear weapons. MAD won’t prevent tactical nuclear weapons from being used like it does for the larger, strategic nuclear weapons. The most poignant threat posed by these weapons is that if they are ever used, they’re not quite destructive enough to prevent a nuclear conflict.

If we hope to live in a world that is not on the brink of nuclear warfare, we cannot continue to fund or deploy tactical nuclear weapons. We cannot allow nuclear-weapon states to believe they can get away with using these weapons, and we must let our lawmakers know that their continued development is unacceptable.

The nonproliferation community is waiting on President Biden’s Nuclear Posture Review with bated breath. As generals call for more of these dangerous weapons, Biden must keep a clear head and resist war planning that could enable their use. And, as lawmakers consider the FY23 Pentagon budget, they should end funding for the maintenance and development of tactical nuclear weapons. To protect humanity, we must never ring the nuclear bell.