In less than one year Brazil, Argentina and Peru have all sworn in new center-right presidents, replacing leaders who had been allies of Venezuelan strongman Hugo Chávez. Last week the South American backlash against chavismo continued its continental sweep when Chile held nationwide municipal elections.

In a rebuke of Socialist President Michelle Bachelet, a majority of Chilean voters refused to support candidates from her ruling left-wing New Majority (NM) coalition. Some 65% of the electorate abstained while a plurality...