US Pre-emptive strike on North Korea seems about to start

US Secretary of State Rex Tillerson has made it clear that The US is considering a preemptive military strike on North Korea. After the missile attack on Syria, Korea, China and Russia have been on notice that they are next on the hit list. Hard to understand why the Generals in the Pentagon think they can win an all-out war on three fronts. The combined military strength of China and Russia easily matches US power and North Korea has enough fire power to be a nuisance.China and North Korea have more than 20,000 missiles on the Korean peninsula. The end result is likely to be the Mutually Assured Destruction feared during the Cold War. The US military appears to dismiss North Korea's missile technology, assuming the Koreans don't have long range missiles to attack the US. But they forget that North Korea has at least 70 submarines, some carrying medium range missiles. So all they have to do is cruise towards the US coast and launch their attack. In the meantime they can attack US bases and warships which threaten them. Most of the missiles in its current armoury have ranges of up to 4000km, but it is developing ones capable of hitting targets 8000 km away.