At the beginning of 2017, upon the inauguration of President Donald Trump, the new administration was informed by U.S. intelligence that while North Korea had developed nuclear arms, the country would take at least four years to develop a delivery vehicle capable of striking the American mainland. The United States acted on the belief that it still had several years to slow or stop the development of the Korean deterrence program before the Asian state achieved basic nuclear parity. With the ability to strike only South Korean and Japanese population centres, North Korea lacked a fully effective deterrent against a U.S. attack. Mutual vulnerability is the essential pillar of deterrence, and so long as the North Korean mainland was within range of U.S. strikes and the U.S. mainland was invulnerable to retaliation, U.S. military action remained at least somewhat feasible. According to intelligence reports the window for action would remain open until 2020 in the very worse case, with most estimated estimating that it would take until 2022 for Pyongyang to gain any form of nuclear parity.
U.S. intelligence's estimates indicated the country had more than enough time to act, leading President Trump to publicly guarantee his supporters that North Korean's gaining of nuclear parity 'won't happen.' North Korea's actions in 2017 did what the country has done since the 1990s - prove Western analysts completely wrong regarding their understanding of the country and outperform all expectations. The speed of its development technologies critical to three pillars of defence in 2017, anti access area denial (A2AD) systems, ballistic missile systems, and nuclear bombs, caught the United States and the entire Western bloc completely off guard.
Early in the year North Korea tested the KN-19 and KN-06 anti access area denial (A2AD) systems, weapons which served not to deter U.S. attacks through retaliatory strikes on its cities - but rather to deny U.S. aircraft and warships access to its airspace and territorial waters by deploying highly sophisticated asymmetric warfare systems. The KN-19 is a long range anti ship cruise missile system on a tracked mobile launcher - which if fielded in large numbers and operating on the move from the country's rough terrain could effectively deny U.S. surface vessels access to Korean waters. The second, the KN-06, is a long range surface to air missile system closely resembling the Russian S-400. The weapon is critical for its ability to deny U.S. aircraft, and potentially cruise missiles as well, from operating North Korean airspace - enhancing the country's already formidable air defence network. It was put into mass production in mid-2017 - and further complicated prospects for a U.S. attack on the country.
Continued in Part Two