ASHINGTON - If the presidential election has already experienced all of the jostling of a whitewater rafting trip, the American people may be about to journey into truly uncharted waters.
At the end of this week, the US Supreme Court will, for the first time in this context, take up a case involving the presidential election.
Depending on the outcome, the contest between Al Gore and George W. Bush could be thrown back to the Florida Legislature for resolution.
At the same time, Congress is researching how it may resolve the battle for the White House, a task that will be all the more complicated if the new US Senate emerges in a 50-50 split - more than a possibility after Maria Cantwell pulled ahead of Slade Gorton last week in Washington state's still-unsettled election.
One possible scene around the bend: Al Gore, the sitting vice president, presiding over the Senate in early January to stymie House Republicans in a bid to use pro-Bush electors chosen by the Florida Legislature. As he looks down from the rostrum, Gore spies his running mate, Joseph I. Lieberman of Connecticut, who would still occupy his Senate seat.
In the case of a House-Senate stalemate, the slate of electors would be chosen by the governor of Florida: Jeb Bush, brother of the Republican nominee.
''This is uncharted waters for everybody,'' said Joseph Little, a law professor and constitutional lawyer at the University of Florida. ''I've never seen anything like this.''
With the legal challenges reaching a crescendo in Florida, the debate about whether Bush or Gore won Florida's popular vote - and thus should receive its 25 electoral votes and thereby the Electoral College majority needed to become president - is moving off a path defined by laws. Instead, it is moving into an arena of judgment by the Supreme Court, the Florida Legislature, and Congress.
There are some historical and legal guideposts, but none completely tested or absolutely clear.
The high court is involved because the Bush campaign has challenged a ruling of Florida's Supreme Court. It gave Florida counties until 5 p.m. today, or 9 a.m. tomorrow if their election offices were closed, to submit the results from any recount of their presidential ballots.
The Texas governor argues that such a decision exceeded the Florida court's discretion, since the US Constitution gives state legislatures the power to set the terms of their elections.
Lawyers say there is no way to predict the Supreme Court's rulings. As a rule, it does not review final state court judgments, but the Bush campaign has evoked federal law to make its case, arguing the Florida court violated Title 3 of the US Code. That is a set of laws from 1948 saying, in part, that if a state court reviews an election dispute, it must do so on the basis of the local laws in effect on Election Day.
Florida law says that election results must be certified on the seventh day after an election, or Nov. 14 in this case. The Florida court extended the deadline so the counties could complete requested hand recounts, but Bush contends that amounted to rewriting Florida law.
In essence, the Bush campaign is hoping for a legal home run, a quick resolution in which the high court rules in its favor, halting the recounts and certifying the Florida results as of Nov. 14. On that date, Bush held a 930-vote lead over Gore.
''The danger for the Bush campaign would be if the Supreme Court said anything that questions the ability of the state Legislature to take control of this process,'' said Jonathan Turley, a constitutional law professor at George Washington University.
The Florida Legislature has already involved itself in the process in two ways. First, it is joining Bush's appeal to the US Supreme Court, arguing that the state Supreme Court usurped its election law powers. Also, it is talking about holding a special session to choose a slate of electors.
Under Title 3, if there is no ''final determination'' of a state's electors six days before the Electoral College is supposed to meet, in this case by Dec. 12 for a scheduled Dec. 18 meeting, then a state legislature has that power.
That could happen if the US Supreme Court rules the state Supreme Court was justified in its decision, but Bush and the Republicans continue litigation in Florida to challenge the results of any of the hand recounts. Such litigation could easily extend past Dec. 12, prompting the Legislature to act.
''You could consider this a `fail-safe' slate,'' said Little, the University of Florida professor. It would also be a pro-Bush slate, since Republicans have a majority in the Florida Legislature.
The Legislature could forward its pro-Bush slate to the Electoral College on Dec. 12. The Florida Supreme Court could also send a competing slate, flopping the dispute into Congress's lap.
At the same time, Gore's campaign plans to head to court tomorrow to challenge a decision in Democratic-leaning Miami-Dade County not to seek a recount. It is also planning legal action in Palm Beach County after election officials there narrowed the scope of ''dimpled'' ballots they would count.
Should the vice president prevail in either of those actions, he might surpass Bush's lead in the popular vote, awarding him a slate of Florida electors.
Should Congress receive two slates of electors, it would vote on which one to accept. This time, Congress meets on Jan. 6 to hear the results of the Electoral College.
If there is a dispute about how Florida's electors voted, the House and Senate would each hold a majority vote to settle the dispute. With the Republicans controlling the House, it would probably support the pro-Bush slate. The outcome of the Senate vote is uncertain, especially if the 100-member body has 50 Republicans and 50 Democrats in the aftermath of the Gorton-Cantwell race.
Should there be a tie, and Gore votes in favor of rejecting the slate chosen by the Florida Legislature, Jeb Bush could indirectly pick his brother as the 43d president of the United States.
Though these scenarios are unlikely, few constitutional scholars could have foreseen what has already transpired since the Nov. 7 election.
One said she feared having the US Supreme Court thrown into such a volatile political arena.
''Up until recently, I've been very much one of the people who felt there wasn't any constitutional crisis,'' said Heather Gerken, an associate professor at the Harvard Law School. ''We were hearing this in the courts. They were resolving the questions in an expeditious way. But in the last few days, I've been wondering whether I have been wrong.
''The court's power rests in willingness of people to accept judges acting in good faith,'' Gerken said. ''If we don't accept their rulings, then we have to wonder about their credibility. The two sides may end up destroying the viability of the courts within the political system.''
