President Alberto Fernández faces a crunch 24 hours as polarised Argentina heads to the polls for crucial midterm legislative elections this Sunday, a vote in which the ruling Frente de Todos coalition could lose its Senate majority.
Nearly half the lower house Chamber of Deputies seats are up for grabs, as well as a third of the upper house in a mandatory vote in which 34.3 million people will cast ballots.
Fernández's Peronist coalition is already a minority in the lower house and analysts believe it risks losing its Senate majority.
The election, as well as determining the make up of Congress, will also set to agenda for 2023, with both the government and the opposition looking ahead to the next presidential election.
In decisive primaries last September, Frente de Todos suffered a bruising defeat, picking up just 33 percent of the vote compared to 37 percent for the president's predecessor Mauricio Macri's Juntos por el Cambio coalition.
"If the results of the PASO [September's primary] are repeated, the ruling party could lose its majority in the Senate," said political analyst Rosendo Fraga of the Nueva Mayoría think tank.
The government has been hard-hit by growing public discontent. Argentina has been in recession since 2018, with GDP dropping 9.9 percent last year due to the coronavirus pandemic.
Citizens are suffering one of the world's highest inflation rates, running at 40 percent so far this year, and a poverty rate of 42 percent for a population of 45 million.
The primaries setback unleashed a political crisis pitting Fernández against his vice-president and coalition partner Cristina Fernández de Kirchner, who pressured her boss into a Cabinet reshuffle in the hopes it would help appease an increasingly-frustrated electorate.
If Frente de Todos loses its Senate majority, the opposition "will most probably use" its legislative blocking power, said analyst Gabriel Puricelli of the University of Buenos Aires.
The ruling coalition would then be forced to negotiate and make concessions if it wants to pass laws or make key appointments, including to the Judiciary.
Since the primaries, the government has been in damage limitation mode, announcing last month a deal with the private sector to freeze prices on more than 1,400 basic goods, following street protests demanding greater food subsidies. It has also increased the minimum wage and family allowances.
The government has rallied its supporters following months of pandemic lockdowns.
Pro-government trade unions and social organisations announced they will march in support of Fernández on Wednesday regardless of Sunday's results.
Many eyes will be on Buenos Aires Province, a traditional Peronist stronghold bastion where the opposition made great strides in September.
There is a potential spoiler in the field, though, in the form of the provocative Javier Milei – an ultra-liberal anti-establishment economist who is pushing for a seat in the Chamber of Deputies representing Buenos Aires City.
Milei has both the centre-right opposition as well as the centre-left government worried, both of whom he has criticised.
The outspoken economist has managed to attract support from all social classes, although some analysts point out most tend to be men aged 18 to 40.
He has caught Macri's attention, though.
"The ideas Milei has been espousing, I have always expressed them," said the former president recently.
Polls will close at 6pm on Sunday the with first results expected around three hours later.