Yesterday, Senator Bernie Sanders (I-VT) weighed in on the standoff in Ukraine with the most comprehensive stance he’s taken on the conflict so far. Liberals, progressives, and socialists should all pay attention.

Writing in the Guardian, Sanders places the blame for the crisis firmly at the feet of the “liar and demagogue” Vladimir Putin and his “gang of oligarchs,” but makes clear his unease with the “familiar drumbeats in Washington” and the “simplistic refusal to recognize the complex roots of the tensions in the region.” Pointing to not just the devastating potential of war in the region, but the ruinous ripple effects that even just imposing sanctions would have on ordinary people in Russia and throughout the world, he urges all parties to “work hard to achieve a realistic and mutually agreeable resolution” — starting with taking seriously the “legitimate concerns” in Moscow about NATO’s eastward expansion.

“To put it simply, even if Russia was not ruled by a corrupt authoritarian leader like Vladimir Putin, Russia, like the United States, would still have an interest in the security policies of its neighbors,” Sanders writes. “Does anyone really believe that the United States would not have something to say if, for example, Mexico was to form a military alliance with a US adversary?”