The INF treaty, which was signed by R. Reagan and M. Gorbachev in 1987, banned ballistic and cruise missiles with a range from 500 to 5500 km. It was the first disarmament treaty that completely eliminated the entire class of already existing weapons, becoming one of the main foundations of the security of Europe. Its importance was recalled along with recurring reports of Russia’s likely violation of the treaty. If the forbidden missiles reappear on the armaments of the Russian army, and there are many indications that this has already happened, it may disrupt the strategic stability in Europe.