What happens if North Korea does launch a nuclear attack against the US?

Perhaps America's best defense against a nuclear attack is the military's anti-missile defense system is the Terminal High Attitude Area Defense (THAAD).

Here is how it works:

According to Lockheed Martin, who was contracted in 1992 to provide the multi-million dollar system, it uses radar to identify a nuclear weapon. It then launches an interceptor from the back of the truck that can safely destroy a nuclear weapon while it's in the air before it hits its target.

However, the system has never been used during wartime.

Israel, on the other hand, has a similar system called the Iron Dome. It was developed with help from the US.

It's in use and has already intercepted hundreds of rockets from Gaza and it's likely saved lives.

The Iron Dome is used for and has proven successful for shorter range rockets.

THAAD uses similar technology but targets longer range missiles.

Lockheed Martin says THAAD has a 100 percent track record in testing since 2005.

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