Despite bluster, US attack unlikely to be a clean win
DESPITE the US President's threats to North Korea, any "massive military response” such as launching an effective attack is far more difficult than it may appear.
The US has a huge arsenal and nuclear bombs capable of annihilating the country, but the North could kill thousands of South Koreans in nearby Seoul before the US could neutralise it.
Part of the problem is knowing where to hit. North Korea is about twice the size of Tasmania and 80% of it is mountainous.
If the US were to launch a pre-emptive strike, it would need to know where leader Kim Jong-un's nuclear sites are, and it's not clear it does.
North Korea expert Brad Glosserman of the Center for Strategic and International Studies in the US said this year he didn't think America knew where the warheads and missiles were.
"The idea that we can intimidate the North Koreans strikes me as being a bit of a stretch,” he said.
Any conflict would also likely result in huge casualties, one reason diplomacy is seen as the preferred option.
"We always have military options, but they're very ugly,” retired US Army general and CNN military analyst Mark Hertling said.
North Korea keeps a huge weapons stockpile in range of the South Korean capital of Seoul and could unleash an attack on its citizens in retaliation for a US strike, potentially killing tens of thousands of people, if not more.
Analysts believe the US may need weeks or months to get in extra troops and equipment including bombers and stealth fighters to support the attack.
Defence and foreign policy analyst at the Cato Institute in the US, Eric Gomez, agreed that destroying North Korea's nuclear forces with a pre-emptive attack would be very difficult.
"The strike would have to locate and destroy most of North Korea's long-range missiles to protect US forces in the Asia Pacific and the US homeland from attack,” Mr Gomez said.
"If the United States also wanted to defend its allies, it would have to destroy as many shorter range systems as possible, which would further complicate the strike.”
The destruction of North Korea's nuclear capability would mean targeting the facilities that make nuclear material and missiles plus leadership locations.
"The United States might be able to pull it off, but I wouldn't give the plan a high chance of success.”
The US probably knew where the big nuclear enrichment and missile factories were located but not the missile units.
North Korea has mobile launchers that can hide and move around the country in tunnels. Its missiles use solid fuel so they can be set up and fired almost immediately, making them harder to destroy before launching.
"The problem is that just one nuclear weapon can cause so much damage. Getting a few missiles is possible, getting all of them or enough of them to have full confidence in US missile defence to take care of the rest would be harder.”
And the North most likely has plenty of chemical and biological weapons ready.
In a worse case scenario, Mr Gomez said the US could use a relatively small proportion of its nuclear arsenal to wipe out all major population centres in North Korea but this would draw international condemnation.
"This would be a horrific act for the US to take and would likely destroy any positive perception of the US in the international community,” he said.
Since taking office US President Donald Trump has reportedly been considering "utterly destroying” Kim Jong-un's nuclear sites using pre-emptive strikes.
Following North Korea's sixth and most powerful nuclear test, Mr Trump reaffirmed Washington would defend itself and its allies "using the full range of diplomatic, conventional and nuclear capabilities at our disposal”, the White House said.
According to US Defence Secretary Jim Mattis, Mr Trump has asked to be briefed on all available military options following North Korea's testing of an advanced hydrogen bomb for a long-range missile.
"Any threat to the United States or its territories, including Guam or our allies will be met with a massive military response, a response both effective and overwhelming,” General Mattis said.
"We are not looking to the total annihilation of a country, namely North Korea,” Gen Mattis said with Joseph Dunford, the chairman of the Joint Chiefs of Staff, at his side.
"But as I said, we have many options to do so.”