A week ago, the US test-launched a ground launched Tomahawk cruise missile.

In doing so, they validated Russian claims that the US installation of BMD systems in Europe were actually in violation of the INF treaty:

Arms Control Twitter has been abuzz since yesterday’s announcement that the United States had conducted a surprise launch of a Tomahawk missile on Sunday afternoon.

This wasn’t just your regular missile launch, however. It was a Tomahawk cruise missile launched from a ground-based Mark-41 Vertical Launch System (VLS), traveling to a distance of “more than 500 kilometers,” according to the Department of Defense.

In other words: a violation of the Intermediate-Range Nuclear Forces (INF) Treaty––if the treaty still existed. It officially died on August 2nd, six months after both the United States and Russia announced suspensions of their respective treaty obligations. But the launch is an important walk-back of US security policy which for 32 years sought to curtail such weapons and instead, as we have written for the Bulletin of the Atomic Scientists, makes the United States needlessly complicit in the INF’s demise and frees Russia from both the responsibility and pressure to return to compliance.

………

Why is everyone so worked up about the launcher?

This is where things get really interesting. The Mk-41 VLS launcher that was used to launch the Tomahawk is the same type of launcher that would be used to launch SM-3 interceptors from Aegis Ashore ballistic missile defense stations in Romania and Poland, once the latter station is completed.

For years, Russia has said that the US deployment of these ground-based Mk-41 VLS launchers to Europe constitutes an INF violation, because they could theoretically be used to launch Tomahawks over 500 kilometers. Legally speaking, this doesn’t hold water––Article VII, paragraph 7 of the INF Treaty states that in order for a launcher to be considered in violation of the treaty, it must actually conduct a ground launch of a prohibited missile. Since this never happened while the INF Treaty was in force, the Mk-41 VLS launchers weren’t in violation.

What’s more, the United States has consistently stated that although Mk-41s can launch Tomahawks, the ones deployed in Romania and Poland cannot. In December 2017, the State Department announced that “The Aegis Ashore Missile Defense System does not have an offensive ground-launched ballistic or cruise missile capability. Specifically, the system lacks the software, fire control hardware, support equipment, and other infrastructure needed to launch offensive ballistic or cruise missiles such as the Tomahawk.”

Perhaps this is true, perhaps it isn’t. But absent some kind of US transparency measure that offers visibility into the Aegis Ashore systems, Russia is forced to rely solely on an American promise. And for Putin, that’s simply not going to cut it. That being said, it’s also possible that no amount of transparency would ever have satisfied Putin, as his primary concern over Aegis Ashore appears to be directed at the general deployment of missile defenses in Europe, rather than their offensive potential.

I actually did work involving these sorts of launchers on naval vessels, specifically on power supplies that could be controlled by software to allow for a wide variety of missile types.

The software could be contained on a memory stick, the hardware is basically a terminal (If that), and the logistical support for a GLCM, which is shipped and deployed as a “ready round”, is minimal.

Once the “Aegis Ashore” launcher is installed, a breakout from the INF treaty could be (and in fact was) executed in a matter of days.