Dozens upon dozens of missiles take flight.For years, the world had heard warnings, but most doubted the day would ever come. Most fall before allied defenses, but one missile finds its mark — it’s the one that matters most. In a flash, hundreds of thousands, if not millions of people perish.

Would North Korea fire off a nuclear weapon? No one knows for certain, but what we do know is that the above scenario is exactly what an aggressive and increasingly-powerful North Korea has been threatening for decades. While the reclusive regime may have previously lacked the necessary weaponry, the North now has the kind of capabilities to turn at least some of its threats into promises.The U.S. and its East Asian allies have strategic defense assets in position, but war is full of uncertainties. “People think missile defenses are a magic wand. They aren’t,” Jeffrey Lewis, a renowned arms expert, told The Daily Caller News Foundation (TheDCNF).

Here’s what happens if the North pulls the trigger.

What Would Happen If A Launch Appeared Imminent?

The U.S. and its allies in the region are by no means unprepared for a North Korean nuclear attack.The U.S. and South Korea both have preemptive strike plans for a situation in which a North Korean nuclear attack appears imminent, and while Japan is considering new options, it still relies heavily on U.S. defense.South Korea has a three-stage defense system, the first stage of which is a preemptive strike option designed to eliminate the North’s offensive capabilities. The “Kill Chain” preemptive strike system detects signs of an impending nuclear missile launch and strikes the North’s nuclear weapons sites and missile bases with cruise missiles and other weaponry.The U.S. and South Korea also have a joint response plan, Operations Plan (OPLAN) 5015.While the specifics for OPLAN 5015 are classified, the plan is believed to consolidate previous contingency plans, specifically OPLAN 5029 (internal instability in North Korea), OPLAN 5027 (preparations for an all-out war), and a peacetime plan involving localized provocations from North Korea. OPLAN 5015 is suspected to call for preemptive strikes on the North’s essential military facilities and weapons, and possibly North Korean leadership.

In the event that a nuclear missile strike appeared imminent, allied forces might attempt to eliminate the North’s missiles at launch. Mike Mullen, the former chairman of the Joint Chiefs of Staff, said last year that the U.S. could move to “take out launch capabilities on the launchpad” if North Korea appeared poised to launch a nuclear armed-missile.The U.S. and South Korea regularly train for such contingencies. For example, during the annual Key Resolve and Foal Eagle exercises, U.S. and South Korean troops practice a “4D” operational plan which involves preemptive military options to detect, disrupt, destroy, and defend against North Korean strikes. The focus is precision strikes on the enemy’s core military facilities and weapons systems.The challenge is that more and more of North Korea’s missiles are on mobile launchers and scattered about the country.

Furthermore, the Korean People’s Army (KPA) has started using solid-fueled missiles, which require significantly less preparation time as they can be fueled in advance and need only a limited crew. Solid-fueled missiles can be fired with less warning and are much harder to track, making them less vulnerable to preemptive strikes.Another issue is that preemptive strikes on North Korea would be much harder to justify diplomatically, especially if war breaks out in the aftermath, which is practically guaranteed.

What If The Nukes Are Already In The Air?

If a North Korean missile makes it into the air, there are plans for that situation as well.South Korea and Japan rely on tiered missile defense.Stage two of South Korea’s three-stage defense system is the Korea Air and Missile Defense (KAMD) system, which is designed to intercept incoming missiles. The U.S. is bolstering South Korean defense through the deployment of a THAAD battery to South Korea, a process that began after North Korea fired four missiles into the Sea of Japan a few weeks ago.