I previously wrote a detailed analysis of the international challenge posed by North Korea. Among other things, it explains how the North’s technological advancement and status as an intractable problem go back much further than one U.S. presidential administration.
As to your specific points/questions:
- Sanctions against North Korea increased, not decreased, from 2009–2016.
- Ratcheting up sanctions further is a reasonable response to the recent missile launch, but it’s unlikely to yield results. It certainly won’t change the North’s desire for a deterrent.
- Deploying carrier groups to the region makes sense as a show of force, and as preparation in the event of hostilities. But threatening actions only increase the North’s desire for a deterrent. And initiating armed conflict would be highly risky.
I support increasing sanctions and moving forces into the region, though I don’t expect they’ll alter North Korea’s national interest or primary incentives.
What I don’t support is wild swings in the president’s approach towards China — seemingly derived from ignorance regarding China’s position and an overconfidence in his ability to convince the Chinese to act against their national interests — nor his failure to accomplish basic presidential duties, such as nominating an Assistant Secretary of State for East Asian and Pacific Affairs.
Given the difficult diplomacy involved with the multilateral North Korea crisis, a permanent head for the Division of Far Eastern Affairs would be especially useful.
