If the president of the United States must decide within minutes how to respond to a dire emergency, its citizens expect him or her to be mentally competent and to act wisely. Because the presidency of the United States is now the world's most powerful office, should its incumbent become even temporarily unable to exercise good judgment, the consequences for the world could be unimaginably far-reaching.
Toole JF, Link AS, Smith JH. Disability in US Presidents ReportRecommendations and Commentaries by the Working Group. Arch Neurol. 1997;54(10):1256-1264. doi:10.1001/archneur.1997.00550220058015