Thirty years ago, the United States and the Soviet Union signed the Intermediate Nuclear Forces Treaty, or INF Treaty, which called for the elimination of all ground launched-surface-to-surface missiles with ranges between 500 and 5,500 kilometers (310 to 3,417 miles). This treaty held through the 1990s and most of the 2000s, but in recent years, there have been allegations of Russian non-compliance.
According to a report by the Wall Street Journal, the United States has begun development of a ground-launched cruise missile. The last such system the United States had in service was the BGM-109G Gryphon, a version of the Tomahawk cruise missile still used by the United States Navy. It was one of three systems scrapped by the United States in compliance with the INF Treaty.
Details on the new missile are scarce, as the system's development has begun. One likely option would be to try to bring back the ground-launched version of the Tomahawk. Another option could be to launch Tomahawks from an Aegis Ashore base. The Tomahawk can be launched from the same vertical-launch cells as the RIM-161 Standard Missile, or SM-3, used in Aegis Ashore. A 2016 release from Lockheed Martin noted that an Aegis Ashore base in Romania is active, and one in Poland is under construction.
The Wall Street Journal noted that the Pentagon's intention is to hopefully force Russia to comply with the 1987 treaty. However, should Russia not go back into compliance, a source told the paper that the United States is determined to be ready if the Russians choose to "live in a post-INF world … if that is the world the Russians want," as one official put it.
The Hill reported that during meetings with other NATO defense ministers at NATO Headquarters in Brussels, Belgium, Secretary of Defense James Mattis states that Russia's violations raise "concern about Russia's willingness to live up to the accords that it's signed, the treaties it's signed."