It's very much worth listening to the podcast (below) of yesterday's Lowy Institute panel session on the Iran nuclear deal, not least because at around 21:00, The Australian's foreign editor Greg Sheridan links the Iran negotiations with North Korea, pointing out that the US has numerous times hailed diplomatic breakthroughs with Pyongyang, only to see North Korea develop nuclear weapons anyway.

 The reason I raise this specific point is that this week's news on the Iran story has crowded out a fairly dramatic nuclear development in North Korea, with a senior US military commander stating publicly that Pyongyang has an operational nuclear-armed inter-continental ballistic missile (ICBM). Here's the video of the press conference by Admiral Bill Gortney, the head of Northern Command (which is tasked with protecting the continental US from long-range missile strikes): 

Note that the US has been warning about the KN-08 missile for some time, but this appears to be the first public statement that Pyongyang has mated the missile with a minituarised warhead and made the system operational. Experts in this field are divided on Gortney's assessment, with some (including the South Korean defence ministry) pointing out that the KN-08 missile has not been flight tested. Others counter that North Korea has previously fielded weapons that were not fully tested, and anyway even if the missile is not reliable, it still has deterrent value. Here's a backgrounder with quotes from expert Jeffrey Lewis on how the US intelligence community might have reached its judgment.

So why is this an important development? Back in 2012 Hugh White wrote a piece for The Interpreter which explains:

Extended deterrence depends on the credibility (to both the adversary and the ally) of US threats to respond to any nuclear attack on the ally with a US nuclear attack on the adversary. Such credibility depends a great deal on whether the adversary has the capacity to hit back at the US. As long as North Korea has no credible capacity to target America itself, a US retaliatory strike on the North carries relatively low risks for the US itself. 

But if the North can hit back, the costs for the US go up dramatically, and the credibility of the US threat goes down. In a crisis, everyone will be asking whether stopping North Korea doing whatever it wants to do is important enough to America to risk a nuclear attack on Honolulu or LA.