People hold pictures of Ukrainian pilot Nadiya Savchenko during a rally outside the Russian Embassy in Kiev on Wednesday. (Sergei Chuzavkov/Associated Press)

THE OBAMA administration keeps betting that Vladi­mir Putin is genuinely interested in a diplomatic settlement in Ukraine. The case of Nadiya Savchenko offers powerful evidence to the contrary.

Ms. Savchenko, 34, is a Ukrainian army officer who served with the U.S.-led coalition in Iraq and later volunteered for a battalion that fought Russia’s invasion of her country’s eastern provinces in 2014. On June 17 of that year, she was captured by pro-Russian forces and transported across the border to Russia, where she “reportedly endured interrogations, solitary confinement, and forced ‘psychiatric evaluation,’ ” according to the State Department. Now she is being subjected to a classic show trial, in violation of international law as well as Russia’s commitments under what is known as the Minsk 2 cease-fire agreement with Ukraine.

On Wednesday, Ms. Savchenko was brought before a court in the southern Russian city of Donetsk to face charges that she served as a spotter for a mortar attack that killed two Russian journalists and a number of fighters. The case is concocted: Not only was the artillery barrage a lawful combat operation, but also Ms. Savchenko’s lawyers say they have video and cellphone evidence showing that she was captured before the incident took place. Ms. Savchenko herself is defiant. Though weakened by a hunger strike, she delivered a lecture to the court predicting a Ukrainian-style democratic uprising in Russia before directing a raised middle finger at the judge.

Ms. Savchenko’s prosecution has inflamed public opinion in Ukraine, where she was elected to parliament and where protests demanding her release attract large crowds. That likely pleases Mr. Putin. The court case, like the continuing attacks by Russian-led forces in violation of the cease-fire, is calculated to destabilize the democratically elected, pro-Western government of Petro Poroshenko. The officer’s detention flies in the face of Minsk 2’s requirement that both sides release imprisoned combatants.

Given Russia’s blatant violations, Mr. Poroshenko, who publicly assured Ukrainians that the peace deal would free Ms. Savchenko, finds it politically impossible to move forward with Ukraine’s obligations, including constitutional reforms. Moscow, in turn, trumpets Kiev’s noncompliance as a reason for Western governments to abandon their support for Mr. Poroshenko and to lift sanctions on Russia.

Fortunately, at least some European leaders see through these crude tactics. Five European Union governments have called for sanctions against Russian officials involved in what they describe as a “fabricated case.” So have 57 members of the European Parliament, who say Mr. Putin should be one of 29 people sanctioned. The United States so far has confined its response to statements by Vice President Biden and Secretary of State John F. Kerry, who both called for Ms. Savchenko’s release this week.

Those words will have no impact on Mr. Putin unless they are linked to actions. The Obama administration should expand its own sanctions on Russia to include all those involved in the detention and prosecution of Ms. Savchenko, as well as other violations of the Minsk 2 agreement. There will be no chance of a settlement in Ukraine unless the costs to Russia of its policy of sabotage and subversion are substantially raised.