Threats of Armageddon are flying between the U.S. and North Korea. President Donald Trump even implied he will launch a pre-emptive strike on North Korea, possibly using tactical nuclear weapons. The Pentagon has a plan to do just that. If carried out, however, it will fail and will likely undermine the real tools of arms control: sanctions and negotiations.
We have been here before. President George W. Bush used a Pentagon plan to attack Iraq pre-emptively in 2003, to prevent a "mushroom cloud." The invasion led to a 14-year tragedy that is far from over.
President Bush could have avoided the Iraq catastrophe if he had followed a basic principle of international law. The United Nations Charter generally prohibits all use of armed force, except in two narrow situations. One is self-defense if an "armed attack occurs;" the other is with UN Security Council authorization if necessary to preserve the peace.
Lawful military force must always be a last resort and must have a high likelihood of success under the principle of necessity. Neither condition can be met in attacking North Korea. The Council just agreed to a tough new set of economic sanctions on North Korea. These have not had a chance to work. More importantly, military force has no track record of success in arms control.