Four potential futures derive from the Monroe Doctrine, some more plausible than others. Which trajectory U.S.-Russian relations will follow in the coming days and weeks—or whether the situation will branch onto a different pathway altogether—remains to be seen.

James Holmes is J. C. Wylie Chair of Maritime Strategy at the Naval War College and a Nonresident Fellow at the University of Georgia School of Public and International Affairs. The views voiced here are his alone.

Image: Reuters.