Why is North Korea testing a nuclear bomb?A nuclear weapon is the ultimate survival mechanism for an isolated regime with little influence and few friends.
Many experts believe North Korea would not use its weapons first. Kim values the survival of his family dynasty and the regime. He knows the use of a nuclear weapon would start a war the country could not win.
Kim also craves international recognition -- and a nuclear arsenal is one guaranteed way to make the global community sit up and take notice. "North Korean leaders know that dead people do not need money, and they believe that without nuclear weapons they will be as good as dead," Andrei Lankov, a professor at Kookmin University in Seoul, South Korea, wrote in an oped for CNN.
Are we going to war?US Defense Minister James Mattis warned of a "massive military response" to any threat from North Korea against the United States. When US President Donald Trump left church on Sunday morning, he was asked if he'd attack North Korea. His answer? "We'll see."
While the US possesses overwhelming firepower compared to North Korea, any American strike on North Korea would likely expose neighbors South Korea and Japan to devastating casualties, analysts say.
Plus, with two launches of long-range missiles this year and the latest hydrogen bomb test, the US homeland may now potentially be at risk of a nuclear strike.
Experts say it's very difficult to verify North Korea's claims, but the very possibility of such a scenario makes the risks of any military action unimaginably high.
What happens if Kim attacks?If North Korea were to strike first -- and last month Pyongyang threatened to send four missiles to the waters off the US territory of Guam and later sent a missile over Japan -- the US has a number of defenses in place.
They include the anti-missile defense system THAAD, which shoots down short, medium and intermediate ballistic missiles, and the ship-based Aegis system, which can track 100 missiles simultaneously and intercept them.
These systems, which analysts liken to a bullet taking out another bullet, could in theory take down a missile with a nuclear payload without detonating it -- although the radiation emitted would still pose risks.