Historedia
AmericasEvent

Juan Lavalle deposes Manuel Dorrego in Buenos Aires

When
1828–1829
Where
Buenos Aires; Buenos Aires (Rosas's assumption of governorship)
Episodes
3

General Juan Lavalle, a Unitarian officer returning from the Cisplatine War, staged a coup in Buenos Aires on 1 December 1828. Encouraged by his party, he deposed Governor Manuel Dorrego, dissolved the legislature, and executed Dorrego without trial. This act reignited the Argentine Civil Wars, leading to political violence against Federals and eventual defeat by Juan Manuel de Rosas.

Episodes

  1. 1 December 1828 · Buenos AiresCoup against Dorrego

    Lavalle, encouraged by Unitarians, led a coup in Buenos Aires on 1 December 1828, deposing Governor Dorrego and closing the legislature.

  2. 13 December 1828 · Buenos AiresExecution of Dorrego

    Lavalle executed Dorrego, his former leader, without a trial, dissolving the second republic of the United Provinces.

  3. 1829 · Buenos Aires (Rosas's assumption of governorship)Defeat and Resignation

    Lavalle was defeated and forced to resign by Juan Manuel de Rosas, who restored pre-coup institutions.

Background and detail

Background. Manuel Dorrego served as governor of Buenos Aires from 1827 to 1828. The 1826 Constitution promoted centralized government, but the war with Brazil stagnated, discrediting the central government. The August 1828 Preliminary Peace Convention affirmed Banda Oriental's independence, causing outrage among locals who desired a united Argentina. This context fueled the political tensions between Unitarians and Federals.

The Coup. Juan Lavalle, a Unitarian military figure, returned to Buenos Aires after fighting in the Cisplatine War. Encouraged by the Unitarian party, he led a coup against Dorrego on 1 December 1828. Lavalle closed the legislature and began a period of political violence against the Federals. He executed Dorrego, his former leader, without a trial, dissolving the second republic of the United Provinces.

Aftermath. Lavalle's actions reignited the Argentine Civil Wars. He was defeated and forced to resign by Juan Manuel de Rosas, who restored institutions existing before the coup. The conflict solidified the divide between Federalists and Unitarians. Rosas assumed the governorship of Buenos Aires in 1829 after forcing Lavalle's surrender, marking the beginning of a new political order.

People involved

Sources

  1. Manuel Dorrego Wikipedia, revision of 2026-10-03
  2. Juan Lavalle Wikipedia, revision of 2026-04-23
  3. Argentine Civil Wars Wikipedia, revision of 2026-09-22

Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.