There are two big reasons President Trump is pulling the U.S. out of the landmark 1987 Intermediate-Range Nuclear Forces, or INF, agreement as of August.

The first is solid U.S. intelligence that Russia has been violating the agreement for years, with the deployment of its SSC-8 ground-launched, mobile cruise missile system. “We really have no choice,” said Trump, arguing that you can’t have an arms control agreement that only one side is upholding.