NAIROBI, Kenya — It was always about more than a single election.

Kenya’s judiciary, which has battled for years to establish its independence, asserted itself last month with a decision that surprised the world, nullifying a tainted presidential election and demanding a repeat to prevent fraud.

It was a moment of democratic triumph, of an independent court defending a young constitution — or at least it seemed like that, until the last minute.

This week, for the second time, Kenyan activists and lawyers pinned their hopes on the Supreme Court, which agreed to hear a petition on the credibility of the new election. Chief Justice David Maraga issued an order requiring all judges to work on Wednesday, despite a hastily declared public holiday, and he promised a 10 a.m. hearing that might make or break the next day’s poll.

But when the time came, only one of the other six judges showed up. Maraga, sitting alone on the bench, announced that, lacking a quorum, the hearing couldn’t happen.

And that is how this battle over Kenya’s democratic institutions ended: abruptly, because not enough judges had come to work.

“It’s an anticlimax,’’ said Haron M. Ndubi, the lawyer who filed the petition. “This is when we were hoping to see the judiciary’s strength play out. We had just started having hope in an independent, strong judiciary, and then suddenly it’s undermined.’’

“It’s like opening and shutting the case on freedom,’’ he added.

His frustration reflects a wider reckoning going on in Kenya, where many people are asking themselves how, after the national trauma of election violence 10 years ago and the enormous steps that have been taken since then, they have ended up, yet again, here — in a muddled election, at the mercy of their leaders, praying for peace.

On Thursday, the country will vote again for president. But the main challenger, Raila Odinga, insists that he will not participate and urged his supporters late Wednesday to boycott the vote, raising the dangerous prospect that millions of his supporters will not acknowledge the outcome.

Only a month ago, the world was lavishing praise on Kenya for the strength of its nascent democratic institutions. Supporters of Odinga, who lost the August poll by 1.4 million votes, embraced a second chance at a win. Even the incumbent who had been declared the winner, President Uhuru Kenyatta, struck a statesman’s pose at the court’s decision.

“I personally disagree with the ruling that has been made today, but I respect it,’’ he said in a national address in September.

But the euphoria turned cynical and the acrimony on both sides grew more heated. Odinga announced his withdrawal from the race, insisting that a new poll run by the same election officials could never be fair and credible. His supporters, and many Kenyan political observers, worried that his withdrawal would leave his 6 million supporters feeling disenfranchised.

Meanwhile, election officials faced threats and intimidation. Last week, one commissioner fled the country and resigned from New York, citing death threats. The same day, the man in charge of the election, Wafula Chebukati, admitted that he couldn’t guarantee that the poll would be credible. On the eve of the Supreme Court hearing Wednesday, the bodyguard of the deputy chief justice was shot by an unknown gunman.

In the days before the new vote, Odinga and Kenyatta refused to speak to each other. Nearly two dozen foreign ambassadors essentially threw up their hands in a joint statement, asking yet again for dialogue and pleading with Kenyans “to choose Kenya’’ and get through the coming days in peace.

The closer Kenya came to the repeat election, the heavier the question felt: After all that has happened, would any poll be considered credible? And if it wasn’t credible, what then?

“Our political system still does not deliver what could cool down the temperature of politics in Kenya,’’ said Bobby Mkangi, one of the nine experts who drafted the new constitution that Kenya adopted in a national referendum in 2010. “Even in the constitution I participated in, I think we didn’t get the state right.’’

The problem, he said, was a winner-take-all-system in which the nation’s democracy fell captive to ethnically driven politics: The bigger the ethnic group, the more likely it is to capture power, especially the presidency.

Kenya’s electoral problems stretch back decades, but the most serious crisis came in 2007, another election Odinga lost. That presidential poll ended with a disputed tally, a media blackout, and a nighttime swearing-in of a hastily announced winner, President Mwai Kibaki.

Widespread violence followed, as Kenyans took to the streets and clashed. More than 1,100 people were killed and hundreds of thousands displaced. The unrest lasted several weeks, and much of it was perpetrated along ethnic lines.