According to the NYT:
[US} officials, who asked not to be identified because they were discussing internal deliberations, said there was no question the missile tests ran counter to the treaty and the administration had already shown considerable patience with the Russians.
The missile treaty is the INF treaty of 1987, which says the US and Soviet Union would “eliminate its intermediate-range and shorter-range missiles, not have such systems thereafter, and carry out the other obligations set forth in this Treaty.”
The NYT report notes this this missile test sits alongside other “irritants” in the relationship including Syria negotiations, the Ed Snowden caper and now the division in Ukraine. This sort of rogue action by Russia, unfortunately, is what the end of the post-Cold War order could look like. China too signs agreements which it routinely disregards (or its government can’t enforce them internally). Of course, this is playing out as the US pushes ahead with a missile shield in Europe. And unlike the twilight of the Cold War there isn’t a careful balance in place between two sides. So while the NYTs headline harks back to the 1980s, the mood may be more early 1950s.