UNTIL last week, Chile's opposition parties were pretty much resigned to losing the next presidential election, due in December, and seeing the centre-left government coalition take a fourth term in office. But now, following a rebellion in the National Renewal (RN), the smaller of the two main opposition parties, the race has been thrown wide open.

Divisions within the opposition alliance—an uneasy marriage between the RN and the more right-wing Independent Democratic Union (UDI)—are nothing new. The RN has long been angered by the perceived steamrolling tactics of its more disciplined and dogmatic ally. It is also frustrated by the lacklustre performance of Joaquín Lavín, hitherto the opposition's presumed joint presidential candidate, who almost defeated President Ricardo Lagos in 2000, but has since lost much of his popular appeal.

The RN nevertheless surprised everyone when, at a meeting on May 14th called to endorse the UDI's Mr Lavín, it voted overwhelmingly to proclaim one of its own former leaders, Sebastián Piñera, as its presidential nominee.

A successful businessman worth an estimated $1.3 billion, Mr Piñera has the advantage of being able to finance his own campaign. His opposition to General Augusto Pinochet in the late 1980s also makes him more acceptable to centrist voters, whereas the UDI remains tainted by its association with the former dictator.

Could Mr Piñera win? His aides predict that in the first round of voting he will come second to Michelle Bachelet, the main government contender, forcing a run-off which he could win by picking up Mr Lavín's votes and those of centrist voters nervous about Ms Bachelet's socialism. But could he rival her charisma?