But the fact that this prospect is regarded as unremarkable, even inevitable, is tribute to the stability of Spain's young democracy, for which Mr Gonzalez deserves much of the credit. Twenty years ago, Spain was a dictatorship, and 15 years ago, it withstood a coup attempt that came within a whisker of bringing back the generals.
But the campaign for Sunday's elections, though fierce, demonstrates the big difference between this political contest and decades of struggle between "two Spains". Those who may have been mortal enemies, are today merely political opponents. Spaniards these days know that polemic and invective are not the same as sedition, and that attacks on the ruling party no longer constitute a threat to the state.
Within a few years of Franco's death in 1975, a peaceful transition to democracy was delicately negotiated among political forces that ranged from the Caudillo's generals to the parties they had persecuted. A constitution was approved that, for the first time in Spain's history, was not imposed by one half of the country upon the other half, but was the product of consensus. Ancient feelings of fear and revenge were softened, enabling the Socialists to take the political centre and win an election landslide in 1982.
The Socialists built up a welfare state, liberalised an over-protected economy and broke the country's isolation by joining Nato and the European Union. They also ran into political trouble, placing at the head of important state institutions cronies who were subsequently banished in disgrace, and they failed - like Spain's rulers down the centuries - to quell the separatists in the Basque country.
Despite Mr Gonzalez's record of political moderation, the centre gradually turned away from him, sickened by the stench of sleaze and the highest rate of unemployment in Europe. Probably his tenure in office was prolonged by the absence throughout the Eighties of a credible conservative opposition. The right was divided, bickering and unconvincing until the young Jose Maria Aznar, just 43, wrenched the Popular Party away from its Francoist moorings to present it as a moderate party of the centre.
Mr Gonzalez entered his seventh, least promising, election campaign reluctantly, drained with fatigue and flayed by the recent murders of two political friends from the early days. Brought low by corruption scandals, aged beyond his 53 years, he sweats on the hustings as he pushes himself to the limit, with little sign of his effortless bubbling of elegance and wit. Even he must feel that only a miracle can bring victory. But charisma still streams from him.
Mr Aznar, by contrast, emits nothing, promises nothing and all but says nothing beyond feel-good expressions of hope, change and renewal. But it is a measure of the tide flowing in the conservative leader's favour that it is not the still-bewitching Mr Gonzalez who has gripped the popular imagination, but the low-key, unflashy Mr Aznar.
Mr Aznar is greeted on the campaign trail with ecstatic frenzy, and his meetings exude the triumphal whiff of victory. The Socialists complain that he is behaving as if he had already won, and even members of Mr Aznar's own camp have warned against selling the pelt before having shot the bear.
But for increasing numbers of Spaniards, the right is no longer frightening; it is, at worst, only an opponent, not an enemy. For a generation who never knew Franco, the Socialists' warnings of a return of the right look like inexplicable scare-mongering. A PP government may slash spending on health, education and pensions - although they say it will not - but is unlikely to bring generals into the cabinet or destroy the unions.
That is not to say the far right has disappeared. It is possible that many sympathetic to the ideals of Franco are sitting quietly within the PP. Should this be the case, it would suggest the strength rather than the weakness of Spanish democracy, and is perhaps more likely to presage a power struggle within the party than a far-right hidden agenda for government.
Mr Aznar may still fall short of an absolute majority, although the last polls before the vote give him a comfortable advantage. If the Socialists' vote holds above 30 per cent, as the polls indicate, they could thrive in opposition and few would write off Mr Gonzalez's chances of a comeback in four or even eight years.
Nearly 50 years ago, during the civil war, the Republicans sang: "Let the tortilla be turned." They meant, let's overthrow the system. (In the words of the song: "Let the poor eat bread and the rich eat shit".)
Today, their country transformed out of all recognition, Spaniards want to turn the tortilla again, but in the more banal sense of clearing out the old rulers to install a fresh bunch. Instead of overthrowing the state, they want merely to change the government.
Today's tortilla is a well-established democracy that the PP shuffled in the pan last year in regional elections when they scooped up provinces and town halls across the country. On Sunday, voters are likely to administer the definitive flick of the wrist.Reuse content