BOGOTÁ, Colombia—Gustavo Petro, once a member of a leftist guerrilla group that fought the Colombian state, was on Sunday elected president after pledging to battle inequality and poverty and insert the state squarely into the economy of a country that is Washington’s closest ally in Latin America.
A 62-year-old senator who in the 1970s and ’80s was in the M-19 rebel group, Mr. Petro is the first leftist and first former insurgent to be elected president in Colombia, a country with a long history of guerrilla conflict. Francia Márquez, a 40-year-old human-rights activist, will become vice president, the first Black politician and second woman to hold that post.
