Ukraine war tests the credibility of credibility

Russia's invasion of Ukraine one year ago this week has forced Americans to contemplate their nation's global credibility more seriously than at any time since the Vietnam War. In deliberating over future aid to Ukraine, the White House and Congress must consider whether and how continued assistance will affect the credibility of American commitments to other countries. International relations theorists and economists have much to say about credibility, yet their abstractions and equations suffer from inattention to human nature. Historical comparison, tempered by wariness of false analogies, provides the most reliable guideposts. Vietnam offers a close historical parallel. In 1965,…