Argentina's Mandatory Primary That Functioned as a National Poll

On August 12, 2019, the Buenos Aires stock exchange dropped 38 percent in dollar terms — the second-largest one-day market collapse anywhere in the world since 1950. The peso lost 15 percent against the dollar by the close. Nothing had been decided. The day before had been a primary, and primaries in Argentina don't pick winners.

What the country had voted in was PASO — Primarias Abiertas, Simultáneas y Obligatorias, the open simultaneous mandatory primary. Law 26,571, passed in December 2009 under Cristina Fernández de Kirchner, requires every party to hold its primary on the same Sunday in August before the October general election, and requires every voter aged 18 to 70 to show up. Parties that fail to clear 1.5 percent of the national vote are barred from October's ballot.

The design problem became visible early. Almost no party fielded competitive primaries; most ran a single ticket against itself. PASO turned, in practice, into a massive opinion poll with legal force — the only national survey conducted with the actual electorate. In 2019, that poll showed Alberto Fernández beating the incumbent Mauricio Macri 47 to 32. The pre-PASO polling had Macri trailing by about 7. Markets had priced in the smaller gap. The 16-point reality wiped out the bet.

Kirchner's original bill had been pitched as a way to consolidate Argentina's fragmented left after a bad 2009 midterm. The opposite happened: it turned the August primary into a pre-election with all the volatility and none of the legitimacy of the real one. On February 21, 2025, Congress suspended PASO for the next legislative cycle with cross-party support. Sixteen years in, the law's most reliable function had been forecasting the October result two months early.