The Supreme Court's decision to become involved in the US election could help reinforce a vital principle of government

In business, in sport and even in poker, man generally obeys a basic law: you do not change the rules of the game after the game has started.

Much of the discomfort of the past three weeks has stemmed from the sense that this most basic axiom of fair play is not being observed in November's highest-stakes game of American politics. If the rules are open to question, that means enduring uncertainty. The effects of this uncertainty have been obvious in the financial markets, the only true casualty of the Florida flap so far.

Businesses have on the whole suffered quietly during the vacillations in Palm Beach and Miami. A thousand times more vociferous have been Republicans outraged at Mr Gore's vote recounts. The terms of the Florida electoral game, they are shouting, were laid out when the cards were dealt, well before election day. How is it that Al Gore can now get away with declaring that one-eyed jacks are wild?

As it turns out, he probably cannot. On Friday, the US Supreme Court announced it would hear the Bush-Gore case in the context of American legal expressions of the fair play principle. This Friday, the justices will listen to argument - and will likely rule soon afterwards. Specifically, the court will look at the decision by Florida's Supreme Court to intervene in the work of Katherine Harris, Florida's secretary of state. It will decide whether the court's action as she certified the election was an ex post facto breach of existing law.

The Bush team feels that the justices are likely to find in their favour and that the quick ruling will deal the death blow to Mr Gore's post-election candidacy. They may have too much confidence on both counts. It is not clear that Mr Bush's lawyers will convince the court that Mr Gore's supporters and Florida's court committed a genuine ex post facto breach - one-eyed jacks may have been wild all along. And it is far from clear that the Supreme Court's word alone will definitively end this extraordinary contest.

Still, the high court's finding will be important to the outcome of the election. What is more, the very fact that the court has chosen to review the matter in the context of ex post facto law is a salutary one for Bush and Gore supporters alike. By focusing on the ex post facto and due process principles, the court practically guarantees that its ruling - whoever it favours - will reduce the uncertainty of future elections by making the terms of the game clearer.

But to the specifics: the court has chosen to review Title III, Chapter 1, Section Five of the US Code, a bit of law written in anger after America's famously crooked election, the 1876 contest between Rutherford Hayes, a Republican, and Samuel Tilden, a Democrat. The statute says that state law made "by judicial or other methods or procedures" before an election "shall be conclusive" whenever there is post-election day "controversy or contest". In other words, no retroactive rejigging.

Mr Gore's lawyers will argue that the recounts and chad inspections that have gone on in Florida were not a retroactive change. They will say that the decision by Florida's Supreme Court to allow local election boards to count chads were part of sanctioned procedure.

The Democrats may have a case. They can claim, perhaps legitimately, that the "judicial or other procedure" clause applies to the establishment of Florida's state Supreme Court. Because Florida vested its Supreme Court with its powers before the election took place, it is not acting retroactively at all.

The Republicans will counter by arguing that the state's Supreme Court was indeed meddling retroactively. Florida already has an officer in place to decide elections, they will say, and intervention by the Florida Supreme Court was an illegal intrusion, as well as an assault on the authority of the legislature.

Like the Democrats, they have good material to work with. They can note that Florida has had creaky voting machines and dimpled chads in place for years. In a close 1988 Senate contest between Connie Mack, the Republican candidate, and Buddy MacKay, the Democrat, a puzzling number of voters left the Senate line on the ballot blank, even though they selected candidates for president and Florida state treasurer. Nonetheless, Florida did not reverse Mr Mack's victory. Nor has the state changed its law enough in the years since then to prevent the dimple problem from re-emerging in Spectacle 2000.

But much of the value of the high court review lies beyond the specific outcome of the Gore-Bush contest, however compelling that outcome may seem at this moment. By reaffirming its commitment to the old Anglo-American notion of honest play, the court is sending a signal that America still adheres to the principles that made it an economic and political force in the first place.

The justices' move recalls the words of James Madison, one of America's founders, who wrote in the Federalist Papers of the dangers of retroactive change. He noted that infuriatingly arbitrary actions of an authority - in that case, the British Crown - were what drove America to revolution in the first place: "The sober people of America are weary of the fluctuating policy which has directed the public councils." The new commitment to certainty was duly enshrined in the Constitution in Article I, Sect 10, which said that no state should pass any "ex post facto law".

That the high court chose to hear a political case in the context of law linked to universal notions of fairness will strike those in business as fitting. In its indirect way, the high court's step is the first genuine acknowledgement we have seen this tumultuous month of the knotty link between commerce and politics. A businessman's solution honouring contract and due process is the best way to ensure that America's false crisis does not become a true one.

© Copyright 2000 Financial Times