The April 22 editorial “The Ukraine dither” has it right. The Obama administration’s nuanced, carefully targeted and, above all, reactive approach to the Ukraine crisis is worse than useless. The existing sanctions are a mockery of justice. Waiting for the worst to happen before imposing new, significant ones essentially allows the worst to happen. It is time for a new, active style of diplomacy.

The United States should specify distinct, concrete and verifiable actions the Russian government must take by a certain date and time, as well as what the United States will do if Russia does not act. For example, within 48 hours, Russia must publicly renounce the armed insurgents in Ukraine, call for them to surrender their arms and vacate government buildings, and move Russian armed forces from the Ukrainian border. Failing this, the president should indicate that the United States will freeze all Russian assets in the United States, boycott certain strategic Russian economic sectors (hydrocarbons, minerals) and suspend all U.S. government-funded cooperative activities with the Russian Federation. Simultaneously, NATO should announce plans to hold a joint naval exercise in the Black Sea and its intention to create a safe maritime channel to Ukraine.

Is this an ultimatum? Yes. It is time for us to act as the great power we at least used to be or to be counted out.

Gerson S. Sher, Washington