Politics in Chile is conducted via a presidential representative democratic republic. There are three branches of governance: executive power is controlled by the government; legislative power is exercised by the government and the two chambers of the National Congress; and the Judiciary, which is independent. The president is both the head of state and the head of government. The president is elected by popular vote for a four-year term and immediate re-election is not allowed. The Palacio de la Moneda in Santiago is the official seat of the president.
Democratic government was re-established in March 1990, after General Augusto Pinochet peacefully stepped down (though he remained Commander-in-Chief of the Chilean Army until 1998). In the early 1970s the country attracted world attention by electing Marxist Salvador Allende, the first democratically elected socialist president in the Americas. Allende envisaged total socio-economic reform under a plan named La vía chilena al socialism, the Chilean Path to Socialism, including nationalization of major industries, government administration of healthcare and land seizure and re-distribution. Allende’s bold socialist policies generated fear in certain circles and in 1973 he was overthrown by a U.S.-backed coup d’état. For the next 30 years Chile was again in the spotlight, but as a notorious example of modern-day authoritarianism.
Pinochet’s brutal dictatorship was responsible for the death, torture and disappearance of thousands of people. Despite at least 300 criminal charges pending against him for human rights violations, tax evasion and embezzlement, a judge ruled Pinochet medically unfit to stand trial in 2004 and he died two years later, at the age of 91.
Economic reforms carried out by the Pinochet government are credited by some as being the grounds for the investment and growth in of the 1990s, which successive government have built on. The current president since 2006, Michelle Bachelet, a separated mother of three and an open agnostic, is the first woman to hold this position in Chile’s history. The campaign platform of the center-left politician was one of continued free-market policies combined with an increase in social benefits.

For further reading try 'Politics in Chile: Socialism, Authoritarianism and Market Democracy' by Lois Hect Oppenheim, Westview Press 2007.