A COUNTDOWN clock hangs over the desks in the open-plan political headquarters of Mauricio Macri, the mayor of Buenos Aires, who hopes to be Argentina’s next president. It tells skinny-jeaned campaign workers how many days, hours and minutes there are “until change”. The clock will hit zero on August 9th, when political parties hold primaries to select their presidential candidates. Then, presumably, it will be reset for the first round of the election itself, to be held on October 25th.

The primaries are less momentous than the clock suggests. There is little suspense about who will win. Mr Macri (pictured, left) is way ahead of rivals to be the candidate of Cambiemos (“Let’s change”), an electoral front that consists of his Republican Proposal and two other parties. The other main contender for the presidency is likely to be Daniel Scioli (pictured, right), the governor of Buenos Aires province. He is the only candidate from the Front for Victory (FPV), the party of Argentina’s president, Cristina Fernández de Kirchner.

Even so, the primaries matter. If pollsters’ guesses are correct, the presidential election is a two-horse race. Sergio Massa, a charismatic congressman from the Justicialist Party who was ahead in the polls a year ago, is far behind now. Ms Fernández, after months of prevarication, has thrown her support behind Mr Scioli, who was Argentina’s vice-president when her late husband, Néstor Kirchner, was president. The primaries are thus likely to show that Argentines face a choice between the continuity that Mr Scioli represents and the change that Mr Macri promises.

Unlike the rowdy presidential primaries in the United States, Argentina’s “simultaneous open obligatory primaries” (PASO) are not an exercise in intra-party democracy. Ms Fernández, who introduced the system in 2009, called it at the time “the most important political reform” since democracy was restored in 1983. There is little evidence for that. None of the candidates faces a serious challenge from within his own electoral coalition. Argentina’s interior and transport minister, Florencio Randazzo, an ally of Ms Fernández, might have posed a threat to Mr Scioli. Mr Scioli extinguished it by choosing the president’s closest (non-family) confidant, Carlos Zannini, to be his running mate. Ms Fernández duly persuaded Mr Randazzo to withdraw his candidacy.

The real point of PASO voting, many analysts think, is to spare politicians nasty surprises in a country where opinion polls are unreliable. Ms Fernández introduced it after her party was routed in mid-term elections. Voters have to take part. They choose which party’s primary to vote in, and that indicates which candidate they are likely to support in the later election. In primaries held before the last presidential ballot, in 2011, the FPV’s contest (between Ms Fernández and a host of others) attracted more voters than that of any other party. She went on to win by a landslide. “In the absence of credible surveys, the PASO elections are a true thermometer for what each candidate’s chances are going into October,” says Juan Cruz Diaz of Cefeidas, a research group.

That has not stopped pollsters from making their own predictions. The only point of agreement is that this year’s presidential contest will be closer than the last one. Aresco, an Argentine polling group, expects Mr Scioli to win in the first round; IPSOS predicts that Mr Macri will prevail in a run-off on November 22nd.

The election is shaping up as a referendum on kirchnerismo, the brand of Peronist populism practised by Kirchner, who became president in 2003, and by his wife, who succeeded him. Mr Macri, a scion of a business family, built his centre-right party from scratch by opposing everything the Kirchners stand for. He promises to restore independence to institutions that Ms Fernández has co-opted, including the judiciary and the statistics agency, to remove trade barriers and currency controls that she imposed in 2011 and to quell inflation. He would probably try to reach agreement with holders of foreign debt, on which Argentina has defaulted.

Mr Scioli is building his campaign around voters among whom Ms Fernández still exerts Evita-like charm. Her image is all over his campaign adverts and billboards. Although inflation is high and the economy is shrinking, a large proportion of Argentina’s 40m citizens benefits from Ms Fernández’s lavish spending on subsidies, benefits and government jobs (see chart). By choosing Mr Zannini to be his running mate, Mr Scioli has greatly improved his chances of holding on to their support.