Sanctions may have isolated Vladimir Putin, but if his deadly convoy pushes on, if he insists on committing mass murder against a sovereign country, we cannot morally stand by.

Perhaps it’s the no-fly zone Zelensky requested Tuesday. Maybe it’s targeted drone strikes on the worst of the Russian armaments. Maybe it’s covert operations, the use of proxy forces, aggressive cyberwarfare, acts of precision sabotage. There are measures short of an all-out counter invasion that we’re certain the Pentagon has been looking into. Moves that would call Putin’s bluff, bloody his nose, give the Ukrainian forces more time, have him think twice about moving forward.

Indeed, they are exactly the kinds of tactics that push the boundaries and gray the lines that Putin has deployed against the international community over several decades.

At the very least, Biden needs to stop saying with certainty that “we will not fight Russia,” as he’s done multiple times. Telegraphing exactly what we will and will not do gives Putin more time and flexibility to tighten his grip on Kyiv.