Russia and China have been avidly modernizing their nuclear arsenals for years; meanwhile, the U.S. arsenal has simply aged. Instead of developing safer, more secure warheads, Washington opted to squeeze more life out of warheads built during the Cold War.

Are those warheads safe today? Yes. Could they be safer? The answer is also yes.

The United States now has plans to improve the safety and reliability of the nuclear warhead that tops its submarine-launched ballistic missiles. The Trump administration’s budget request for the National Nuclear Security Administration revealed a program to develop the “W93” warhead to replace the W76 or W88 warheads now arming the Navy’s Trident II D5 missiles.

Some of those old warheads were produced as early as 1976—the same year Bill Gates dropped out of Harvard to devote his time to Microsoft. Gates is retired now, and just like him, these warheads are aging out. By the early 2040s, they will be too old to function safely and reliably.

There might be a way to extend the life of these warheads for a little longer. But just as one might not feel safe in a 1976 Ford Explorer come 2040, relying on the deterrence from a warhead on its last leg is not reassuring. Instead, the administration proposes to start replacing them with the W93 in the early 2030s.

The goal here is to give our submarines a more secure warhead. According to a senior defense official, the W93 design will be largely based on existing nuclear components but include new parts to make it safer and more reliable.

In what way would the W93 be safer? Existing warheads rely on high explosives to provide the heat and compression needed to start a nuclear reaction. One way to increase a warhead’s safety is to replace conventional high explosives with insensitive high explosives.

They aren’t called insensitive because they lack feelings. Rather, insensitive explosives require significantly greater pressure shock to detonate than do conventional high explosives. In the event of accidents like an airplane crash, a fire, or even a lightning strike—not unheard of for nuclear weapons—insensitive explosives will not “go off,” thus preventing an unintended nuclear detonation.

Moreover, using insensitive explosives in a warhead improves security from threats like theft during transportation. With less concern over accidental nuclear detonation, more focus can be given to simple and effective security operations.

Who wouldn’t want a nuclear weapon that could include this feature?

The alternative to developing the W93 would be to modify or extend the life of warheads already in the nuclear stockpile. But those warheads were designed based on Cold War military requirements, which typically prioritized a weapon’s operational effectiveness over its safety. Often this meant making it as powerful as possible while limiting the weight to increase the missile’s range. Safety was only a secondary concern in these designs.

Other warheads of the ‘80s put a premium on miniaturization as well power. The W88 was designed to deliver a high explosive yield but be small enough so that multiple warheads could be fitted on a submarine’s missile. Even though the developers considered using insensitive explosives in these warheads to enhance safety, they opted to go with conventional high explosives because they take up less space.

Designers of the W93 would not have to face such a tradeoff. Since the 1980s, U.S. technology has advanced enough to provide the flexibility to meet both military and safety requirements.

Opponents of nuclear modernization have questioned the need to start the W93 this year, which is sooner than had been previously predicted. But, considering the National Nuclear Security Administration’s seven-phase production process, as well as research and development efforts needed to develop accompanying fuzes and aero shells, the agency will have to begin this project as soon as possible if it is to deliver a working W93 by 2034.

And given the chance to increase warhead safety, why wait another day?

The fiscal year 2021 budget request for the W93 includes $32 million to begin work on the system’s aero shell and $53 million to begin work on the warhead. That seems a modest price to pay to start building a safer nuclear warhead.