As within the United States debates have arisen over how much unilateral power the President has to deploy force, so too debates are being raised across Europe. Depending on each country’s history, system of government, and economic status, various historic positions are shifting. Public, as well as elite, voices are shaping the debate. Another point of tension is NATO’s changing role as countries develop autonomous war caveats. Extended analysis of how Great Britain and Germany are grappling with these concerns has great import for U.S. policy. Learning to skillfully persuade its European allies will gain the United States better cooperation from those who do not share the U.S. war powers model.