The Trump administration may not have many diplomatic wins to speak of but it should get credit for its moves on the Intermediate-Range Nuclear Forces (INF) Treaty.
The INF treaty, signed by Presidents Gorbachev and Reagan 30 years ago, banned ground-launched cruise missiles with a range of 500-5000 kilometers. The title INF treaty because the treaty banned all intermediate-range weapons.
Upon taking office, the Obama administration began to harbor suspicions that Moscow was cheating on this treaty as it now customarily does on arms control agreements. The administration did not go public until 2014, did not specifically list the weapon in question, and failed to retaliate or persuade major European allies who are the targets of these Russian weapons.