Do we still need nuclear submarines?

While Russia's nuclear subs might not be up to much these days, the United States is still putting its subs to use. That said, we need some nuclear submarines -- we just need fewer of them, and there's no longer the need for the subs to be outfitted with nuclear warheads. In this post-Cold War era, the deterrent threat of submarines is actually greater if they're outfitted with weapons that navies can plausibly use. Nuclear subs today are likelier to be equipped with Tomahawk missiles that have conventional explosive payloads than with nuclear missiles they'll likely never fire.

­A submarine powered by onboard nuclear reactors has a nearly limitless range and superior maneuverability; what's more, it can be placed in far-flung waters across the globe with no need to surface except for crew provisions every three months or so. So while the technology behind nuclear missiles might not be doing us a lot of good today, the innovation of the nuclear reactor is still serving at least six international navies. The U.S., Russia, Great Britain, France, China and India all have nuclear submarines in their fleets.

And many more nations have diesel-electric subs, the alternative to nuclear submarines. Diesel-electric subs also have good range and can stay submerged for days on end. They're much quieter underwater running on electric power than a nuclear submarine is. Compared to nuclear subs, diesel-electric submarines do have a few drawbacks. For one, they must surface periodically to refuel and recharge. Additionally, they must stay in range of a friendly port, so they're not as quick to respond to crises around the globe. By contrast, a nuclear submarine can lurk for months off the coasts of geopolitical hot spots, such as the Persian Gulf.

A small number of submarines have been converted to serve in special-forces operations, such as extracting or depositing Navy SEALs onto the shores of enemy nations. Modified Ohio-class Trident submarines are now outfitted with Tomahawk cruise missiles, some of which are topped with tactical nuclear warheads. But are these missiles really necessary? Some argue that there are real benefits to staying prepared in the face of adversity. Submarine-launched missiles strike their targets with a nuclear payload in a mere 15 minutes -- land-based missiles take 30 minutes to reach their targets. Of course, timeliness is only advantageous if you're attempting to annihilate a foe with an overwhelming first strike.

As far as we know, there's no nation on Earth that can neutralize all of the United States' spread-out and concealed missile silo sites, as well as all of its airborne nuclear capabilities. So it would seem that keeping hundreds more nuclear warheads lurking beneath the sea is a superfluous measure. Take Trident submarines, for instance. Each of these can carry up to 24 ballistic missiles, and each missile can deliver up to eight different warheads. These subs could be converted to serve pragmatic, tactical non-nuclear military functions or dedicated to civilian research and exploration.

The majority of the Navy's oceanic research has been dedicated to military purposes. In recent years, the Navy has begun more actively making its nuclear submarines available for use by the scientific community. These subs are ideal for traveling to polar locations, remaining submerged at great depths for long periods of time and serving as self-contained nautical research laboratories, even in the harshest climates. So while there may no longer be a need for submarine-mounted ballistic nuclear missiles, the capabilities of nuclear-powered submarines -- and the flexible role they can play for military and scientific use -- seem to justify their continued production.