When Russian President Vladimir Putin ordered an invasion of Ukraine in 2014, Secretary of State John Kerry was stunned. “You just don’t in the 21st century behave in 19th century fashion by invading another country on completely trumped up pretext,” Kerry sputtered on Face the Nation. I recalled Kerry last week as I watched reactions to a brazen act of mid-air piracy carried out by Belarusian authorities. A commercial airliner full of passengers flying from Athens to Vilnius was forced to land in Minsk so that an opposition blogger could be arrested by security services. There was shock and outrage similar to Kerry's on display across Western capitals, but there was also a note of helplessness and resignation. “We will be super-concerned and demand his release,” an unnamed EU diplomat told a Financial Times journalist. “But the EU can’t do much, sad as it is.”

One can make all sorts of arguments in defense of the diplomat’s resignation—from “it would be too costly to escalate” to “there is no guarantee that escalation would yield desired results” to “freeing Belarus of its tyrant is simply not that important to the West.” All these are fine realist critiques of a more activist policy and are almost certainly being bandied about in the halls of power, both in Brussels and in Washington. More interesting, though, is the fact of the European diplomat’s sad resignation itself. The arc between Kerry’s outburst and the diplomat’s candid admission—from bluster to despair—can be read as the slow but steady decay of an overly idealistic worldview that has shaped Western foreign policy from at least 2008.