Donald Trump, an ongoing eruption of self-refuting statements (“I’m a very stable genius” with “a very good brain”), is adding self-impeachment to his repertoire. Spiraling downward in a tightening gyre, his increasingly unhinged public performances (Google the one with Finland’s dumbfounded president looking on) are as alarming as they are embarrassing. His decision regarding Syria and the Kurds was made so flippantly that it has stirred faint flickers of thinking among Congress’ vegetative Republicans.

Because frivolousness and stupidity are neither high crimes nor misdemeanors, his decision, however contemptible because it betrays America’s Kurdish friends, is not an impeachable offense. It should, however, color the impeachment debate because it coincides with his extraordinary and impeachment-pertinent challenge to Congress’ constitutional duty to conduct oversight of the executive branch.

Aside from some rhetorical bleats, Republicans are acquiescing as Trump makes foreign policy by and for his viscera. This might, and should, complete what the Iraq War began in 2003 — the destruction of the GOP’s advantage regarding foreign policy.

Democrats were present at the creation of Cold War strategy. From Harry Truman and Dean Acheson through Sen. Henry Jackson and advisers such as Max Kampelman and Jeane Kirkpatrick, they built the diplomatic architecture (e.g., NATO) and helped to maintain the military muscle that won the war. But the party fractured over Vietnam, veering into dyspeptic interpretations of America’s history at home and abroad, and a portion of the party pioneered a revised isolationism. Conservative isolationism had said America was too virtuous for involvement in the fallen world. Progressive isolationism said America was too fallen to improve the less-fallen world.

Hence Republicans acquired a durable advantage concerning the core presidential responsibility, national security. Durable, but not indestructible, if Democrats will take the nation’s security as seriously as Trump injures it casually.

Trump’s gross and comprehensive incompetence now increasingly impinges upon the core presidential responsibility. This should, but will not, cause congressional Republicans to value their own and their institution’s dignity, and exercise its powers more vigorously than they profess fealty to Trump. He has issued a categorical refusal to supply witnesses and documents pertinent to the House investigation of whether he committed an impeachable offense regarding Ukraine. This refusal, which is analogous to an invocation of the Fifth Amendment protection against self-incrimination, justifies an inference of guilt. ...

— George Will is a columnist for The Washington Post.

— George Will is a columnist for The Washington Post.