The day before Russian President Vladimir Putin flexed his muscles in Ukraine, the columnist Jeffrey Goldberg asked President Obama whether, given his failure to police his own “red line” in Syria, countries like Russia and Iran still believed he was capable of using force to advance American interests. Repudiating the inference, the president pointed to his threat last fall to intervene militarily with targeted strikes in Syria. That threat, he averred, was directly linked with the support subsequently given by both Russia and Iran to the agreement stripping the Assad regime of its chemical weapons: