The Trump administration is suspending compliance with the Intermediate-Range Nuclear Forces (INF) Treaty as a prelude to fully withdrawing:

Giving up on the INF Treaty is one of the biggest blunders that Trump has made as president, and it could prove to be one of his costliest mistakes. While there is still a period of six months for the president to reverse course, there is very little chance that will happen. Bolton has wanted the INF Treaty gone for decades, and now he is in a position to ensure that it won’t survive. The president cites Russian violations of the treaty to justify this decision, but this is an excuse rather than a real reason to tear up a major arms control agreement. James Acton notes that the U.S. has abandoned other successful agreements when the other parties were complying with them, and that makes it hard to believe that complaints about violations in this case are the real reason for leaving:

When a treaty has worked this well and has been as good for U.S. and allied security as this treaty has been, it is absurd to throw it all away when it can still be salvaged. The administration made the bare minimum of effort to resolve outstanding disputes with Russia, and they are practically jumping at the chance to kill the treaty. Leaving this treaty bodes very ill for the survival of New START, which expires in two years, and once both treaties are dead there will be nothing left to constrain the growth of the U.S. and Russian nuclear arsenals.

The INF Treaty has been one of the most successful arms control treaties ever negotiated. It was the cornerstone of U.S.-Soviet and then U.S.-Russian arms control for the last thirty years. When it goes, there isn’t going to be anything to replace it for a long time to come. We are about to enter a very dangerous and unstable period in U.S.-Russian relations, and the U.S. and Russia could soon be in a new arms race that neither country needs.