The Framers undoubtedly assumed that the legislature would do its work while assembled in some physical location. In 1787, they scarcely could have imagined any other way of proceeding. Various other constitutional provisions thus refer to Congress as “meeting” (Article I, Section 4) or “assembling” (Article I, Section 3), and one even provides a mechanism by which members can compel “the Attendance of absent Members,” presumably meaning those members not otherwise present where Congress is meeting.
None of the clauses in which those terms appear is actually about how Congress casts or counts its votes. Indeed, neither the document itself nor any Supreme Court decision defines what counts as “attendance” or “assembling,” much less how such “attendance” may be taken, or such “assemblage” may be accomplished. What the Constitution does instead—as the courts have repeatedly recognized—is leave it up to each house of Congress to “determine the Rules of its Proceedings,” as Article I, Section 5 specifies. As the Supreme Court has explained, as long as there is a “reasonable relation between the mode or method of proceeding established by the rule and the result which is sought to be attained,” the content of those rules is “beyond the challenge of any other body or tribunal.”
This constitutional flexibility has enabled Congress to embrace the various informal solutions that it has long used to “do business,” such as counting on members to give “unanimous consent” to a vote even if something less than a majority of members is present. These tools, which some may hope will suffice in current circumstances, are themselves hardly a model of democracy. When working as intended, votes by unanimous consent, for example, leave it up to a minority of Congress’s members, often the leadership, to take the place of an actual expression of majority will.