Robert Gates was U.S. secretary of defense and therefore my immediate boss for much of my time as supreme allied commander at NATO. A former director of the CIA and a career intelligence officer, he is brilliant, understated and dry-witted. When asked once about our ability to predict wars, he said, "Our record is consistent and perfect -- we never get it right."
With that as a cautionary comment, I would assess the chances of a full-blown war on the Korean Peninsula in 2018 are in the range of 10% and rising, with an additional 20% chance that some level of ordnance will be exchanged (missiles, torpedoes, artillery) but that both parties will step back from the abyss of a nuclear war. A year ago, I would have placed the chance of war at around 1%. Two things have changed: rapid technical progress by the North Koreans on their missile and nuclear programs; and the unsteady belligerence of the U.S. administration of President Donald Trump -- a combustible and potentially lethal combination.