Are Trump and Putin Opening Pandora’s Box?

Consider this: Modern nuclear-armed cruise missiles will be far more fearsome than those that were banned when the I.N.F. Treaty was signed in 1987. Advances in computer electronics and guidance technologies have produced conventionally armed cruise missiles that can be commanded to change their routes and targets in flight, and loiter to attack at a programmed time.

With such capabilities, cruise missiles could be launched from many locations at once and could be detonated on numerous targets at once. The warning available would at best be ambiguous, no different from sensing the presence of shadows in a dark forest.

These terrifying new capabilities on both sides would substantially escalate the chances of a catastrophic accidental use of nuclear weapons during some as yet unforeseen crisis.

How did we get here? The path to the current crisis can be traced to September 2009, when President Barack Obama announced a new approach to American missile defense in Europe against long-range Iranian missiles. It would replace the George W. Bush administration’s plan for what was called Ground-Based Missile Defense sites in Poland and Romania, and Mr. Obama described his new Aegis-based European Phased Adaptive Approach as a “smarter and swifter” defense system. The installations would have a larger number of smaller and slower interceptors that would be guided by Aegis radars, normally used on United States Navy warships.

What Mr. Obama apparently did not know was that none of the radars associated with his program could see long-range Iranian warheads at a long-enough range to launch interceptors. That was a scandalous blunder, ascribable only to a lack of technical information from the Department of Defense and a failure of the White House and State Department policy staffs to adequately vet for the president the implications of the proposed change.

President Obama was probably also not told that the “Aegis ashore” installations in Poland and Romania could be armed quickly with offensive cruise missiles that would pose a threat of an immediate and ferocious attack on European Russia with only short warning.

In other words, the decision to place Aegis installations ashore in Europe produced no credible missile defense capabilities for the United States, but did create installations that could be rapidly armed with dozens — or hundreds — of offensive cruise missile

That is what the Russians have been reacting to since shortly after Mr. Obama decided to proceed with his plan.

Now the Trump administration’s stated reason for threatening to withdraw from the I.N.F. is Russia’s development of the SSC-8 cruise missile, also known as the 9M729, which appears to violate the clear limitations on weapons ranges established by the I.N.F. I leave it to others to argue whether the Russians have indeed violated the treaty; it is quite possible they have. But the SSC-8 missile appears to have characteristics similar to those of America’s Tomahawk sea-launched cruise missile. The Tomahawk could readily be stored at and launched from the Aegis sites.

Western news organizations have often treated as obfuscation the Russian claim that American missile defense installations have an offensive capability. But publicly available information makes it clear that the Aegis-based systems in Eastern Europe, if equipped with cruise missiles, would indeed violate the I.N.F.

Because the Aegis systems have so little use in interdicting Iranian-launched long-range missiles, it would be reasonable for Russian military planners and political leaders to wonder why the United States decided to base them in Eastern Europe. Could that decision indicate a strategic intention to expand and modify the system over time (which is happening now)?