Recent health-related absences by Representative Tom Kean Jr. and former Senate Majority Leader Mitch McConnell have revived questions about what happens when members of Congress cannot perform their duties. The article argues that, while Congress can refuse to seat or expel members, there is no defined constitutional process for replacing legislators who remain in office but are incapacitated or absent for long periods.

The Constitution sets age, citizenship and residency requirements but does not address health, mental capacity or attendance; expulsion requires a two-thirds vote. Senators’ vacancies can generally be filled by gubernatorial appointment, whereas House vacancies require special elections. With the House currently comprising 218 Republicans, 212 Democrats and one Republican-aligned independent among 431 members, prolonged absences can make a narrow majority harder to manage.