The sad fate of Terri Schiavo preoccupies the US in this, one of our most religious seasons. But it was probably unwise of Republicans to lead Congress in intervening in the decision to remove the severely brain-damaged woman's feeding tube. Nor was President George W. Bush's decision to jet back to Washington to sign off on congressional efforts a good idea.

Such abrupt and direct interference signals that Congress may freely disturb either a) the principle of the separation of powers; or b) the rights of states and their courts.

Ted Kennedy described the Republicans' action as "arrogance". For once, the senator for Massachusetts is correct. If some future liberal-left Congress intervenes on behalf of a pregnant woman who wants an abortion in the fifth month of pregnancy, the "Right to Lifers" now in Congress will have only their prissy selves to blame.

Members from both parties voted to move on the Schiavo case. Underlying the precipitate action, however, is a problem that the Republicans have done more than Democrats to illuminate. The nation's judges are generally to the left of the population politically. Many of the judges want to use individual cases to rewrite big chunks of law on questions such as euthanasia. Republicans want a more restrained judiciary.

Yet Democrats are using an old device - the filibuster, the act of deliberately prolonging debate to prevent legislative action - to block Republican nominations to federal judgeships. They are also castigating Republicans for daring to advocate filibuster reform.

In this second instance, Mr Kennedy accused Republicans of trying to "run roughshod over the institution of the Senate". His colleague, Robert Byrd of West Virginia, went further by likening Republican efforts to end use of the filibuster to Adolf Hitler's 1933 power grab - seemingly legal but outrageous.

Such breathless defences of filibustering are every bit as sanctimonious and foolish as the Republicans' euthanasia rescue.

To see all the ironies here, it helps to review the history of the filibuster. In many cases, a simple majority vote will suffice to pass a law in the Senate. But a minority opposition party can block that majority by filibustering and preventing the vote from taking place. Today, it takes 60 votes to override a filibuster; Republican senators, who number fewer than 60, want to reduce the rule to a simple majority.

Contrary to the impression currently given by Democrats, there is nothing holy about this arrangement. Every new Congress has the opportunity to keep, change, or do away with the device. What is more, it is downright strange to see Democratic liberals such as Mr Kennedy suggest otherwise. For during much of modern history, the filibuster or tricks like it were used to subvert their most beloved causes.

In the very early years of Congress, anti-slavery petitions flooded Capitol Hill. Yet lawmakers adopted a "gag rule" that said all such petitions must be disregarded without action.

From a seat in Congress, John Quincy Adams assailed the gag rule for years. He was clearly acting on principle rather than the weekend advice of a focus group. His persistence and the pure moral force of the argument convinced Congress to pass change in 1844. Adams's career gained nothing - he had already been president when it happened. But he celebrated in writing: "Blessed, forever blessed, be the name of God."

More recently, southern conservatives used the filibuster, also known as Rule XXII, to block civil rights legislation. In the period after the second world war, two-thirds of the Senate, or a full 69 votes, was required to end a filibuster. Congress successfully and routinely used filibusters to withhold rights from black people. In 1957, Strom Thurmond, a Democrat senator from South Carolina, set a record with a 24-hour 18-minute diatribe.

Again, the reformers fought for change but punctiliously, via legal and procedural paths. Paul Douglas, a Democrat representing Illinois, laboured for years, Adams-like, to weaken Rule XXII. The senator failed so often that he penned a parody of Lewis Carroll's White Queen: "A Rule XXII change yesterday; a Rule XXII change tomorrow; But never a Rule XXII change today."

Douglas was the sort of character who could have been played by Spencer Tracy and his campaign was, again, more about principle than personal advantage. In the end, the Senate saw fit to reduce the number of senators required to override a filibuster to 60 in 1975. By then, Douglas had been out of office for nearly a decade.

The current Republican campaign to exempt nominations from filibuster is part of the same traditional legal move by a democratic republic, not, despite advertisements, a "nuclear" move.

The larger point here, however, is that the hassle of procedure can be a good thing. It prevents Congress from acting rashly, as in the Schiavo case. Because filibusters and filibuster rules are so hard to overcome, they force legislatures to consider carefully the reason for ending or altering them. Citizens, in turn, respond better when lawmakers demonstrate over time that their projects are worthy.

The Republican "limit the filibuster" effort is a serious campaign. But it is hard to take seriously when, on other measures, the party leaps to play the fool.

© Copyright 2005 Financial Times