In the U.S. Senate, only one-third of the members stand for election every two years; the rest carry over from one congressional term to the next. In this regard the Senate differs from the House of Representatives, where all members stand for election every two-year cycle. That much is familiar, but what legal consequences flow from this structural difference? According to some legislators, courts, and commentators, this difference is very important in that it makes the Senate, but not the House, a "continuing body." The continuing-body idea is invoked to defend highly controversial aspects of Senate practice. By far the most familiar context in which the idea arises - and the one with the most potential for generating serious conflict - is the debate over the legality of the filibuster. Under the current Senate rules, it is extremely difficult to restrict or eliminate filibusters, for any attempt to amend the Senate rules can itself be filibustered. Further, precisely because the Senate is considered a continuing body, these nearly unamendable Senate rules never expire but instead remain in effect indefinitely. As a result, the Senate's supermajoritarian rules are entrenched against future majoritarian change. The continuing-body idea is thus used to justify an outcome that would otherwise seem to conflict with the usual principle that current legislative majorities are not bound by their predecessors' decisions.
95 Iowa Law Review 1401-1466 (2010)
Bruhl, Aaron-Andrew P., "Burying the “Continuing Body” Theory of the Senate" (2010). Faculty Publications. 1771.