The future of Spain's fragile new democracy may be at stake here in the Spanish Basque country, four feud-ridden provinces wedged up against France and the Bay of Biscay.

Guerrillas of the Basque independence movement ETA have claimed responsibility for the killings since Oct. 1 of 59 national policemen, military officers, judges, employers or other "tools" of the Spanish state.

Spanish generals defied military discipline by calling on the centrist government of Premier Adolfo Suarez, fighting an uphill reelection campaign, to crack down on the Basques.

The last major poll before the vote on Thursday indicated the three Basque nationalist parties would raising their lower house representation to 14 seats from 9.

The poll also showed Suarez's Center Democratic Union losing seats but remaining the most important party, while the Socialists were projected to be the biggest gainers, coming within a dozen seats of the Suarez party in the 350-seat lower house.

A great number of Spaniards, especially in the officer class, have made it clear that they would prefer to return to authoritarianism than see the Spanish nation splintered.

Contrary to the impression that the Madrid government tries to create, an-in-depth tour of the region showed that there is far more basic sympathy for the separatist movement than is generally conceded.

Hatred for Madrid and all it represents is a constant conversational theme. The Spanish police are widely regarded here as a military occupation force. The police, knowing they are potential assassination targets, act like occupiers. They travel in convoys with their sirens screaming. They jump out of their cars with submachine guns at the ready.

The police are socially ostracized and live with their families in compounds surrounded by barbed wire and machine guns.

"You may as well wear a target on your back as to put on a Civil Guard uniform," said one of the rare Basque members of a local city police force. The Civil Guard is the national gendarmerie, much hated here, that many associated with the late dictator Francisco Franco.

Basque hatred is reciprocated by the police.

"It is very difficult for the Spanish government to control the police," said Ramon Sota, a senatorial candidate of the Basque National Party, the moderate major nationalist group. "They are still Francoist. They must be sent back to school to be taught democracy." All three Basque nationalist parties place priority on their demand that the Spanish police in the Basque country be replaced with locally controlled forces.

"Madrid is a very dirty word here," said Sota. His 84-year-old party, known by its Spainish initials, PNV, the traditional vehicle of Basque nationalism and the most powerful party in the region, gives the impression of being separatist. "On the road to independence, we'll get something else first," said Sota.

Suarez's foreign minister, Marcelino Oreja Aguirre, who is likely to lose his bid for a parliamentary seat from San Sebastian, the basque contry's second largest city and the intellectual center of Basque nationalism, said in a campaign meeting this week:

"The PNV has done a lot of harm. It pronounced itself against violence but not against the goals of violence. It says no to independence, but adds, for now. Such ambiguity is a moral encouragement to ETA.... For us, autonomy is an end in itself. For the others, it is only an intermediary stage."

A number of PNV leaders, ranging from the party's business-oriented wing to its socialist-inclined one, were asked the same question: "If an ETA man came to the door of the average party worker in the middle of the night and said he needed to be hidden from the police, what would happen?"

To a man, the party leaders gave the identical answer -- the ETA man would be taken in. "After all," said one. "ETA is Basque and the police are Spanish. You wouldn't expect a Basque to turn over another Basque to the Spaniards, would you?"

Despite the interplay between ETA and the Basque National Party, they are not pursuing the same objective. The party's leaders are middle-class professionals. Its left wing seems no more extreme than Sweden's Social Democrats. ETA wants social revolution. Mirentxu Purroy, editor of Egin, the newspaper closest to ETA, described the organization's goal:

"ETA's strategy is provocation to force the government to intervene militarily and show who really rules in Spain. Democracy is a sham here... The autonomy statute for the Basque country was vetoed by the army... So its first targets are invariably the army and the police to make the army react."

In Bilbao, the Spanish civil governor Luis Alberto Salazar Simpson admitted, "you can't organize the Basque country without the PNV," so its ambiguity is a major problem for Madrid.

Both the party and ETA called for a boycott of the constitutional referendum in December, and 63 percent of the eligible voters stayed home or cast no or blank ballots -- compared to 40 percent in Spain as a whole.

Even though the PNV got only about a quarter of the region's vote in the first post-Franco elections in 1977, it has Tammany-like control of the region. It is expected to better its showing significantly on Thursday.

The party has about 50,000 members.All the other parties in the Basque country combined proabably do not total a quarter of that. Party clubhouses all over the Basque country, legal only since Franco's death, serve as community centers, with bars, restaurants, meeting rooms and social services.

Party meetings on Sundays are often all-day affairs with picnics, folk singing and dancing and traditional strenuous competitions like boulder moving. There is mass, so the faithful can attend both church services and the party outing.

The RNV's relationship with the Catholic Church is a complex blend of anti-clericalism and attachment to the faith that has deep roots in Basque history.

Basque extremism is often compared unfavorably in Madrid with the supposed reasonableness of Catalonia, the other major region with a language and culture of its own. The nearby Catalans brought the head of their government-in-exile home from France after Franco's death and made him head of their provisional autonomist government. The PNV has insisted that the head of the Basque government stay in exile in Paris.

King Juan Carlos, the symbol of Spain's smooth transition to democracy, has been received in triumph in the Catalan capital of Barcelona. He has not yet dared visit the Basque country.

Yet it is widely assumed that the quiescent Catalans are just waiting to see what the Basques get and that they will demand as much for Catalonia.

There are 7 million people in Catalonia, and 2.7 million in Euzkadi, the Basque name for the Basque country, out of 36 million in all of Spain. The Basques' per capita income is 32 percent higher than that in Madrid.

Since 1950, 600,000 persons have settled in the Basque country, attracted by the now depressed steel and shipbuilding industries. The Basques call those Spaniards "immigrants" and are generally cold to them. But many Basques do express pride that after two generations or so, "immigrants" often start to become Basque, sending their children to the network of private schools that teach the Basque language and Basque nationalism. These Spaniards often express the zeal of the convert.

Only about 30 percent of the population can actually use the language in their daily lives, mostly the old and the very young. During most of the 40 years of Franco's rule, the language was illegal.