CONSTANTINE, ALGERIA -- Algerians vote today in the first free elections since the country won its freedom from France in 1962, and many are worried about a victory by Moslem fundamentalists seeking to establish an Islamic republic in this north African nation.

The absence of reliable polls makes the outcome of the nationwide municipal and regional elections impossible to gauge as the country goes through its most serious crisis since the ruling National Liberation Front (NLF) led it to independence in an eight-year war that left a quarter of a million Algerians dead.

Here in Constantine, eastern Algeria's cultural and religious capital, residents believe that they set in motion the events that led to the elections and the end of the socialist NLF's one-party rule.

In 1986, striking high school students and unemployed youths here went on a rampage, attacking signs of NLF power and privilege such as party headquarters, state stores and party cars. They were encouraged by cheering citizens who leaned out of windows to let the young rioters know that this most conservative of Algerian cities approved of their actions.

Social ferment then grew in this country of 24 million, leading to week-long riots in October 1988 that were sparked in part by economic problems brought on by low world prices for oil, the nation's chief export. After the army shot and killed at least 150 people, President Chadli Bendjedid promised political and social reforms. A new constitution was approved by voters in February 1989, paving the way for today's election, in which the ruling party will face a variety of smaller parties as well as independent candidates.

During the campaign, this ancient mountain citadel of 450,000 people has been seen as important because of its conservative religious tradition. Nearly all Algerians are Sunni Moslems, and the local congregation of ulemas, or religious scholars, has influence among Algerian Moslems far beyond Constantine.

That tradition prompted Bendjedid to open his campaign here with a warning that politics has no place in the mosque -- even if older Algerians remember that the NLF once used the pulpit to further its own policies.

Bendjedid -- and many other Algerians -- expresses concern about the popularity of the fundamentalist Islamic Salvation Front, which calls itself the leading opposition party and for months appeared to be the only well-organized political force in the country.

Its bearded leader, Abbassi Madani, last month staged a rally here. His spellbinding appearance drew thousands impressed by the front's religious solution to the country's serious economic and financial crisis.

But Madani's populist demands to replace the NLF with an immediate Islamic state got a mixed reaction from the ulemas, who have traditionally set a less political agenda for Algerian Moslems.

Constantine residents, moreover, argue that fundamentalism is less attractive here, where tight family relations remain important, than in coastal cities, where alienated young supporters cut off from their roots provide the bulk of fundamentalist strength.

Local politicians said they feel Madani no longer represents an unstoppable political force -- at least in Constantine. "The fundamentalists are spinning their wheels," said Ali Kechid, the leader of a small Marxist party that often has served as the favorite whipping boy for Madani's fiery oratory. "But they are still far from collapse."

In line with their conservatism, Constantine residents appear not to like extremism. That was the lesson learned by the NLF's 41-year-old Nourredin Djellouli, who was sent to the region last year to help organize the party's campaign efforts.

"Constantine is conservative and rejects any form of extremism -- and we know because we learned the hard way," he said.

Djellouli encouraged the local NLF rank and file to remove the discredited post-independence generation leadership and choose a virtually entirely new slate of candidates, for the most part university-educated men in their thirties.

"But it's still very hard to be effective after 27 years of anti-democratic practice," Djellouli said. "If the NLF wants to have a future it has to change its basic style and practice and open up."

Politicians who agree about little else regret the lack of a coalition front against both the NLF and the Islamic Salvation Front, noting that three separate lists of independents could neutralize each other.

"This apprenticeship of democracy is all so new to us," said Ahmad Benyahia, a Paris-trained painter who is running as an independent to save the architectural monuments of Constantine's old town.

But for the grizzled war veterans gathered at their headquarters, the NLF was and will always be their only allegiance. "If another party takes over," said a gray-haired former regional commander, referring to the Islamic Salvation Front, "we are here to ensure Algeria doesn't jump the rails."