China is undoubtedly a nuclear power — but in terms of nuclear stockpiles, its estimated 300 or so warheads doesn’t sound like much of a threat compared to America’s standing stockpile of 6,800 or so — but then, that’s the thing about nukes. You really only need one to change the face of the globe, destabilize entire regions, or push a reluctant giant into nuclear war.

Although the United States and Russia spent the better part of the Cold War competing over who could build more or bigger nukes, in a post-Cold War world, nuclear weapons have stopped serving as the looming boogeyman that kept us up at night, and started serving as a deterrent against their own kind. The world’s few nuclear nations now largely maintain their arsenals using a “second-strike” mindset — ensuring their nation is capable of retaliating against a nuclear attack, rather than seeking new ways to mount such a strike themselves.

That approach serves as the crux of the modern “mutual assured destruction” strategy. In order to maintain your nation’s second-strike capabilities, it’s integral to maintain a variety of launch platforms, delivery methods, and nuclear weapons themselves, so no single attack could neuter your ability to deliver holy-hell to the offending nation that hit the red button first. America’s nuclear triad, for instance, relies on intercontinental ballistic missiles (ICBMs) that travel under their own power, bombs (or missiles) delivered via aircraft, and of course, Trident II submarine-launched ballistic missiles (SLBMs) to create a well-rounded means of delivery that ensures no attack could stop America from retaliating.

The idea is simple: as long as other nations know launching their own nukes will result in their own destruction, they won’t launch them. Thus far, it’s worked for more than 70 years.