North Korea's sixth nuclear test prompted a flurry of early analysis and speculation about whether the Hermit Kingdom had successfully developed a thermonuclear weapon. Some media outlets referred to the test as a "game changer."
Such a label is more hype than truth, but the sixth nuclear test does show that time is not on the United States' side; assuming U.S. leadership wants to negotiate.
The longer Washington waits to begin talks, the more advanced Pyongyang's arsenal will become and the larger its leverage grows. The growing power of North Korea's nuclear arsenal should worry American policymakers and analysts to a degree, but concern over the sixth nuclear test should be placed in a broader and more worrying perspective.
A North Korean thermonuclear weapon is not a true "game changer" because it does not change the nature of the United States' problem. Thermonuclear weapons have higher explosive yields than nuclear or fission weapons, but both types can cause incredible levels of devastation. The political purpose of North Korea's nuclear weapons program is to deter U.S. military action by threatening unacceptably high costs on the U.S. These costs can be inflicted by either a thermonuclear or nuclear weapon, and while North Korea has only miniaturized its fission weapons recently, it has possessed this kind of weapon since 2006.
North Korea's Hwasong-14 intercontinental ballistic missile (ICBM) was more of a "game changer" than a thermonuclear weapon because the ICBM gives Pyongyang the ability to hold the U.S. homeland at risk. The ability to hit U.S. cities with nuclear weapons significantly increases the effectiveness of North Korea's nuclear deterrent vis-à-vis the U.S. North Korea's newly tested thermonuclear weapon can inflict significantly more damage to U.S. cities than other nuclear weapons it has tested, but the precise degree of damage is far less important than the ability of the weapons to reach the U.S.
Joining "the H-bomb club" is the latest in a string of technical accomplishments in North Korea's nuclear and ballistic missile programs that complicate Washington's ability to negotiate with Pyongyang. The longer the U.S. holds off on negotiations, the more technical hurdles North Korea will overcome. This in turn makes it more difficult for the U.S. to negotiate for limited aims, such as a freeze on new kinds of missile technology or nuclear weapons development, while strengthening North Korea's hand in negotiations on more weighty issues like a peace treaty or denuclearization.
As more technical milestones are reached, the more difficult it will be for the U.S. to slow down North Korea's program and the harder it will be for the U.S. to get what it wants in negotiations with Pyongyang in the future. Tightening U.S. and international sanctions against North Korea may slow down its progress in designing, building, and testing new capabilities, but the North Koreans have a lot of practice dodging sanctions. Moreover, many of their latest technological accomplishments seem to be homemade, which further reduces the ability of sanctions to stop their progress.
The Trump administration has not signaled any willingness to open negotiations with North Korea, and the tendency of the administration to ratchet up pressure in response to North Korean missile tests suggests that more sanctions and military posturing are likely in response to the sixth nuclear weapons test.
Negotiating with North Korea may be diplomatically challenging and politically unappealing, but the U.S. needs to seriously consider opening talks sooner rather than later. The current U.S. strategy of "maximum pressure" has failed to curb North Korea's missile testing and did not prevent the sixth nuclear test from taking place. The war of words between the U.S. and North Korea will likely escalate until another missile is inevitably tested, leading to another round of sanctions and heated rhetoric. Rinse and repeat until Pyongyang has survivable solid-fuel ICBMs with miniaturized thermonuclear warheads.
Negotiations may not result in a big U.S. political victory, but the current action/reaction cycle, with no negotiation, is doing little to slow North Korea's technical development. The longer Washington waits to talk, the worse the situation will become.