The governing Broad Front has campaigned on its achievements in implementing a social agenda that has improved life for the poor, allowed gay marriage and created the world's first national marketplace for legal marijuana. The opposition coalition has capitalized on growing disenchantment over slower growth and rising insecurity in the South American nation of 3.4 million people.
Analysts say neither of the top two contenders among 11 candidates has enough support to secure a victory in the first round, setting the stage for a runoff in November. Polls give Daniel Martínez, the former mayor of Montevideo who is the Broad Front's candidate, between 36% and 43% support, while Luis Lacalle Pou, leader of the National Party and candidate for the coalition, has 24% to 28%. To win outright, a candidate has to get 50% of the ballots plus one vote.
"What's at play is continuing with a model that is looking to align growth with equality, with an emphasis on an agenda of new rights for minorities, or a change toward more market-friendly policies that respond to the demands for more order and public safety," political scientist Adolfo Garcé said.
Uruguay has enjoyed strong economic growth since the Broad Front took power in 2005. Poverty fell dramatically, from about one-third of the population in 2006 to just over 8% as people saw their purchasing power climb.
Broad Front administrations also have adopted a series of progressive laws such as legalizing gay marriage, abortion and the sale of marijuana in pharmacies. But the coalition, led by outgoing President Tabaré Vázquez, has hit choppy political waters: An education reform aimed at tackling a high school graduation rate of only 40% failed, Vice President Raúl Sendic had to resign in 2017 over corruption allegations, and a record 414 homicides last year has made public safety a pressing concern. Economic growth has slowed and unemployment is up.
"There's a possibility of a return to the past, or sticking to a process of change and social justice," the Broad Front's Martínez, 62, said during a televised debate.
An engineer by training, Martínez was a union leader at the Uruguayan state energy company before he left government to work in the private sector. He returned to lead the same energy company and went on to become minister of industry and energy. He is an avid cyclist who sets aside time for long rides every weekend.
The National Party's Lacalle Pou, 47, is a longtime legislator with deep political roots — his father was president in the 1990s and his mother was a senator. He ran for president in 2014, losing to Vázquez in a runoff.
Political scientist Daniel Chasquetti said Lacalle Pou has moved more to the center since then. On the campaign trail, he has plugged not only his own policies, but those of a range of other center-left and right-wing parties that he hopes will help him form a government.
"I support him because he is young, with education and he seems to really want to do things properly," said María Eugenia Genche, a retiree.
Others, like Camilo Romero, a teacher, aren't convinced. "Lacalle is very prepared, but in my view he represents interests and an economic position that would directly affect people in weaker positions in the short- and medium-term," Romero said.
Although the Broad Front leads in the polls, Garcé, the political scientists, predicts it has the more difficult path to victory, and needs to secure at least 45% of the votes Sunday to have a realistic chance in the second round.
The parties that have been running third and fourth in the polls, including a new right-wing party led by an ex-military commander, have said they would back Lacalle Pou in a runoff.
Voters will also be electing 99 deputies and 30 senators while deciding on several referendum questions, including whether to assign part of the military to a new unit that helps with public safety, add life imprisonment as a penalty for serious crimes, allow judge-approved nighttime raids, and repeal the possibility of early release for people convicted of the most serious offences.