I gave a quiz today on the Panama Canal and that time period in America. During that time, the Monroe Doctrine added to with the Roosevelt Corollary. The Monroe Doctrine had said that European nations should not mess with the affairs of the Western Hemisphere.
The quiz was matching terms to defintions. One of my students had written in little reminders next to the terms so that he wouldn't forget. Next to Monroe Doctrine he wrote "doctor who helped with diseases in Panama." When he did the matching, he decided on the right option, so he must have rethought that through!