New Delhi, Feb. 20 -- Bolivia's long-serving socialist former leader, Evo Morales, reappeared Thursday in his political stronghold of the tropics after almost seven weeks of unexplained absence, endorsing candidates for upcoming regional elections and quieting rumors he had fled the country in the wake of the U.S. seizure of his ally, Venezuela's ex-President Nicolas Maduro.

The weeks of hand-wringing over Morales' fate showed how little the Andean country knows about what's happening in the remote Chapare region, where the former president has spent the past year evading an arrest warrant on human trafficking charges, and how vulnerable it is to fears about U.S. President Donald Trump's potential future foreign escapades.

The media out...