Voting in Bolivia is mandatory, and on Sunday lines began to form outside schools converted into precincts even before polling places opened at 8 a.m. Soon, patios filled with voters, who entered classrooms one by one to fill out paper ballots, then dropped their votes in cardboard boxes, to be counted by hand later that night.
Many called the moment critical one, and said they had arrived despite fears of the coronavirus. "This is going to define our country's destiny," said Enrique Huanca, 58.
Sunday was a redo of last year's election, and came at a time of deep polarization, at a level notable even for a country accustomed to division and unrest. In the weeks leading up the election, the United Nations documented at least 41 acts of political violence.
In the streets of La Paz, the administrative capital, there is little agreement about whether there was electoral fraud last year. And Mr. Morales's party, the Movimiento al Socialismo, or MAS, is casting doubt on the voting system, warning supporters of almost certain "electoral fraud" and a process stacked against them.
A recent poll by the nongovernmental organization Fundacion Jubileo found that just 40 percent of Bolivians trust the country's electoral body, despite major efforts to overhaul it since last year.
It could take days for results to come in.
And when the count is announced, large swaths of the country are likely to be angry, political observers say, and violence is a real possibility.