Congress, through a provision in the National Defense Authorization Act, risks endangering American national security by threatening the integrity of the Intermediate Nuclear Forces Treaty. The INF Treaty between the United States, Russia and twelve former Soviet republics prohibits the deployment of intermediate-range missiles, which have historically proven dangerously destabilizing. The original American goal of the treaty was to eliminate the Russian SS-20, a deadly ballistic missile; over time, treaty negotiations grew in scope to also include cruise missiles.
Source