The six counties that use punch-card machines, including Los Angeles and San Diego, already were scheduled to replace them in time for the March 2 presidential primary, which would become the likely date of the recall election if yesterday's decision stands.
The state allowed counties to use the machines in the November 2002 election because there was not enough time to replace them, but agreed they would not be used after this year.
The ruling almost certainly will be litigated further, and the three-judge panel that issued it gave lawyers for the state seven days to appeal.
The case could quickly land at the U.S. Supreme Court. If it does, it would become the first major test of Bush vs. Gore, the decision that stopped the recount of Florida's votes in the 2000 presidential election.
The three appeals court judges who issued yesterday's decision based it primarily on that high court precedent.
Even with the prospect of further appeals, however, the decision created new complications in a campaign that already has baffled many political strategists.
Davis and each of the major candidates to replace him pledged to continue campaigning until a final ruling. The major campaigns said they would continue their television advertising as scheduled.
But with uncertainty over the election date, candidates who built their campaign plans around a six-week election now must consider the possibility of one lasting six months.
Californians who already have voted - about 200,000 - were left uncertain whether they would get a chance to vote again if the election were postponed. Secretary of State Kevin Shelley issued a statement saying voters who planned to cast absentee ballots should still do so.
State lawyers face questions on whether postponing the election would mean reopening the ballot to new candidates - or allowing existing candidates to remove their names - because state law generally requires that the ballot be set within 59 days of the election.
And voting officials, already struggling to produce an election on a short deadline, were handed a new problem - whether combining the lengthy recall ballot with the primary in March would produce a behemoth too large for the newer voting machines to handle.
"It's more than a wrinkle," said Los Angeles Registrar-Recorder Conny McCormack. "No one even asked the largest county in the state if we had the capacity to run it in March. The answer is no."
While Davis sought to maintain a studied neutrality in his public statements, he smiled broadly and appeared upbeat as he discussed the court action with reporters.
The governor took pains to point out that he was not involved in the suit and that he supported the "right" of those who signed the petitions to have the election.
"I would like a result, however, that allows as many Californians as possible to vote," he said. "I do think the prospect of a small voter turnout overruling 8 million people is not good for democracy," he said, referring to the number of people who voted in last November's election. "It violates the sanctity of the electoral process."
Voting rights are "the core of our democracy," said Lt. Gov. Cruz Bustamante, the only major Democratic candidate on the ballot to replace Davis. "We're confident [the courts] will come to a carefully thought-out and considered decision. We will continue our campaign until there is finality in the courts."
Republicans, by contrast, denounced the ruling - and the three judges, all appointed by Democratic presidents, who produced it.
"I want to remind people that the 9th Circuit is the most reversed court - the same court that banned the words, 'Under God' in the Pledge of Allegiance," said Republican state Sen. Tom McClintock, referring to a decision last year by a different panel of 9th Circuit judges, who sit in San Francisco. "This election is called for by the Constitution and demanded by the people of California."
"Historically, the courts have upheld the rights of voters, and I expect that the court will do so again in this case," said Arnold Schwarzenegger, the other major Republican candidate in the race. "The people have spoken, and their word should - and will - prevail."
The judges - Harry Pregerson, Sidney R. Thomas and Richard A. Paez - acknowledged that postponing the election undoubtedly would be a burden and an expense for the state and the candidates.
But, they said, the hardship would be greater for voters whose ballots were not counted because of flaws in voting machines. The six counties that have been scheduled to use punch-card machines in this election included 44 percent of the electorate in the last election. State officials have conceded that the punch-card machines lead to miscounting 3 percent to 7 percent of ballots.
"The state has an interest in holding a fair election - one trusted by the candidates and the voters to yield an accurate and unbiased result," they wrote in their joint opinion.
"The high error rate associated with the decertified machines to be used by 44 percent of the voters in October would undermine the public's confidence in the outcome of the election. The margin of victory could well be less than the margin of error in the use of punch-card technology," they wrote.
The Los Angeles Times is a Tribune Publishing newspaper.