LIMA, Peru — Michelle Bachelet’s imminent return to the Chilean presidency could mark a watershed for the Latin American left.

As widely predicted, Bachelet, a moderate socialist who previously led her country from 2006 to 2010, won by a mile in Sunday’s first round of voting and is expected to handily defeat her rival on Dec. 15.

She beat her nearest opponent Evelyn Matthei, a former labor minister in the deeply unpopular outgoing conservative government of President Sebastian Pinera, by 22 percentage points, and only narrowly missed the 50 percent hurdle needed to avoid a runoff.

With ironclad democratic credentials, and a commitment to both markets and effective state regulation of them, Bachelet, 62, represents an alternative to the autocratic left-wing populists who often hog the limelight in Latin America.

Like Uruguay’s President Jose Mujica and Brazil’s President Dilma Rousseff, Bachelet was once imprisoned and tortured for opposing right-wing military dictatorships.

And like them now, she is quietly offering to ease poverty by redistributing wealth while also respecting a free press and democratic checks and balances, rather than attempting to concentrate power in her own hands.

Unglamorous they may be — Mujica, a former guerrilla, is in his 80s and famously lives in a rundown farmhouse — but the trio’s brand of social democracy appears to have legs in a region still wracked by poverty and where many are tired of corrupt and authoritarian politicians.

Bachelet finished her term as president with an 84 percent approval rating. But she appears set to return to La Moneda, Chile’s presidential palace, by moving leftward in response to the waves of protest that rocked Pinera’s government.

That unrest came despite annual economic growth near 6 percent over most of his term, thanks partly to high copper prices. Yet many Chileans are unhappy with the country’s high levels of inequality, as well as absolute poverty.

Policies she is now offering include free higher education, gay marriage, abortion in certain limited circumstances such as rape or danger to the mother’s health, and raising corporate tax from 20 percent to 25 percent.

She also wants to redraw the Pinochet-era constitution that was designed by the brutal dictator to block change.

The constitution requires majorities of 57 percent for education reform and 67 percent for constitutional reform, among others. It also gives half the seats in each electoral region to the losing party unless the winning party gets more than two-thirds of the votes.

On current projections, Bachelet is unlikely to win the necessary congressional majority to push through those changes and will be forced to negotiate with her opponents.

How she does so could lay down a marker in the region where analysts say leaders such as Venezuela’s Nicolas Maduro and Ecuador’s Rafael Correa have treated their legislative majorities as blank checks to bully opponents and ride roughshod over institutions such as the courts.

Yet a changing of the guard may now be occurring in the Latin American left.

Venezuela is on the brink of economic collapse. Inflation there runs at more than 50 percent after more than a decade of price controls and a disastrous fixed exchange rate. And Maduro appears to lack the political savvy and charisma of his mentor, the late Hugo Chavez, to manage the crisis.

Meanwhile, his ally in Argentina, Cristina Fernandez de Kirchner, is increasingly unpopular due to yet more economic problems and allegations of high-level corruption. Her party recently failed to garner enough votes in legislative elections that it had hoped would allow her to change the constitution to run again when her current presidential term ends in 2015.

Of Latin America’s populist leftist leaders, arguably only Ecuador’s Correa has currently been able to maintain both the personal popularity and growing economy that could keep him in power — with constitutional changes to stop him terming out — for years to come.

And Bolivian President Evo Morales also appears likely to continue in power — after controversially reinterpreting the constitution to allow himself a third term — although fewer in the region may regard his economic template as a success story.

But now, with Bachelet’s impending re-election, has that Latin American model of populist, autocratic left-wing leaders taken one more step toward the end of its shelf life?