By Monica Machicao and Daniel Ramos
LA PAZ (Reuters) - In the Bolivian city of El Alto that clings to vertiginous mountain peaks soaring above political capital La Paz, the country's ruling socialist party faces a reckoning in regional elections to be held on Sunday.
The socialist candidate for mayor, hand picked by party grandee and former President Evo Morales, is far behind in opinion polls. The likely winner: Eva Copa, a former party star - young, female and indigenous - pushed out of the party for being too moderate.
Morales made a triumphant return to Bolivia last year when his Movement for Socialism (MAS) party swept back into power, his close ally and former minister Luis Arce elected as president.