In announcing his decision to withdraw from the 1987 Intermediate-range Nuclear Forces (INF) Treaty, President Trump cited Russia's repeated violations and the fact that the treaty does not bind China, which is engaged in the world's most ambitious ballistic missile development program. But Trump's withdrawal may also be designed for another purpose. It sends a subtle but unmistakable message to North Korea: If you refuse to denuclearize, we can now surround your country with short- and medium-range missiles that will allow us to strike your regime without warning.