The Pentagon has researched what it would take to build a kind of missile banned under a Cold War-era treaty—in an effort to pressure Russia to stop using those very missiles. Officials tell the Wall Street Journal they are "laying the groundwork" necessary to build ground-based, intermediate-range missiles banned under the Intermediate-Range Nuclear Force Treaty (INF) signed by the US and Soviet Union in 1987 as part of a new US strategy on Russia. Officials say Russia has been in violation of the treaty since 2012, which the Washington Post reports led congressional Republicans to lean on the Obama administration to do something. A year ago, it did ask Russia to cop to its production, but received only a denial. US intelligence determined the missile was actually used in February.
The US has reportedly told Russia what it is up to (which the Journal notes is currently in compliance with the INF), as well as that its work will be abandoned if Russia once again complies. Researching and developing missiles with a range of 500 to 5,500 kilometers is permitted under the INF; actually producing, testing, and deploying is not. "We need to send a message to the Russians that they will pay a military price for violation of this treaty," an official says. Meanwhile, Russia denies any violations and in fact accuses the US of violating the INF via its missile defense systems in Romania and Poland. The Post notes the defense policy bill being considered by Congress would enable the development of the missile by way of a $58 million allocation.