Republican frustration over Democratic opposition to some Bush judicial appointments is threatening the separation of powers. Senate majority leader Bill Frist says unlimited debate is inapplicable to votes on judicial nominations. He says the Senate is obligated to have an up-or-down vote.
But there is no basis for this in the Constitution or in Senate rules or precedents. The filibusters that Republicans find so objectionable are rooted in the right of unlimited debate: If opponents can talk long enough, there will be no vote, and whatever they are opposing will fail.
There is no such right in the House. This is one of the basic differences between the two bodies. It stems from the concept that the House is the popular body representing people, while the Senate is the deliberative body representing states. This was the fundamental compromise that made possible the agreement leading to adoption of the Constitution in 1787. The Senate was (and is) the protector of small states and, by extension, of minorities.
The filibuster was rarely used in the 19th century, even during the bitterness leading to the Civil War. It didn't become a major issue until early 1917, when it was used to defeat a bill to arm merchant ships. Under pressure from President Wilson, this led to a new rule in the Senate providing that debate could be ended by a two-thirds vote (Rule XXII).
Following the civil-rights debates of the mid-20th century, this was amended to provide for cloture - the procedure to close debate and put an issue to immediate vote - by a three-fifths vote (60 instead of 67) except with respect to changing the rules.
It is being argued that the Senate ought to adopt its rules anew at the start of each Congress, opening Rule XXII to amendment. This argument has been made before but never prevailed. The Senate is generally regarded as a continuing body whose rules carry over from one Congress to the next. This is another difference between the Senate and the House: Every member of the House is elected (or reelected) every two years; senators serve overlapping six-year terms, so the Senate never starts afresh.