SANTIAGO, Chile — Former President Michelle Bachelet won a landslide in primary elections for Chile’s opposition Sunday, making her the favorite for presidential elections in November, after pledging to raise taxes and spending.

Bachelet, who led Chile from 2006 to 2010, garnered 73.1 percent of the vote, while Andres Velasco, her closest rival and a former finance minister, had 13 percent, according to the Electoral Service website. In the ruling coalition, Pablo Longueira edged ahead of Andres Allamand with 51.4 percent of the vote to 48.6 percent.

“It’s a shoo-in for Bachelet” in the November election, said Patricio Navia, a political science professor at New York University. With five people voting in the opposition alliance primary for every two voting for the ruling coalition “this weakens the right wing and it weakens the president.”

The administration of President Sebastian Pinera has been undermined by two years of student protests in support of improved education, even as the economy expanded more than 5 percent in each of the past three years.

Bachelet, a member of the Socialist Party, has promised more spending on education, paid for by a five-percentage-point increase in the corporate tax levy and a cut in the amount of money companies can put aside for future investment without paying tax.

The primary “was a triumph for demands for a quality education that is free and dignified for every boy and girl in the country,” Bachelet told supporters after the vote. “You have consecrated a project that will take education from a consumer good to a social right.”

LAME DUCK

The government ordered police to storm schools across Santiago last week that had been occupied by students demanding an end to profits in the education industry. The schools were taken over by the army and used as polling stations.

Pinera “was a lame-duck president before this vote, but this puts all the nails in the coffin,” Navia said by phone from Santiago.

Longueira’s victory for the ruling coalition makes a Bachelet win in November even more likely, Navia said. The Independent Democratic Union, Longueira’s party, was created in the 1980s by civilian officials in the dictatorship of Augusto Pinochet.

A poll by Central University on June 17 and 18 had showed 65 percent of people expected Allamand to beat Longueira. The survey of 300 people didn’t ask for voter preferences and had a margin of error of 5.65 percentage points. A MORI poll also concluded that Allamand would win, without giving percentages.

Bachelet, constitutionally banned from running for a second consecutive term, had taken a break from politics to lead UN Women, a gender-equality agency created in 2010, the same year she left office.

Her success in November’s election would return her coalition to power after a four-year hiatus. The bloc, which includes Bachelet’s Socialist Party and Christian Democrats, had ruled Chile since 1990, when Pinochet left office.

As a 23-year-old medical student, Bachelet was detained and tortured by officers of the dictatorship in 1975. The year before, Bachelet’s father, Air Force General Alberto Bachelet, died in jail of a heart attack after being tortured on suspicion he opposed the coup that toppled Socialist President Salvador Allende.

Bachelet completed her studies in East Germany after being exiled to Australia. An agnostic and divorced mother of three in a Catholic country, she defied social norms on her return to Chile and rise to power.

Chile’s ruling coalition was thrown into turmoil earlier this year when its leading presidential candidate, Laurence Golborne, was forced to remove himself from the primaries when it was revealed he has money in an offshore account registered in the British Virgin Islands. He hadn’t registered the savings when declaring his assets to Congress.

As mining minister, Golborne had led the rescue of 33 miners trapped underground in northern Chile. The rescue is being turned into a film with Antonio Banderas and Jennifer Lopez.