In April 1982, Galtieri had been in office for four months and his popularity was low.
On 2 April, and on his orders, Argentine forces invaded the Falkland Islands, a United Kingdom territory subject to a long-standing Argentine claim.

Initially the invasion was popular in Argentina, and the anti-junta demonstrations were replaced by patriotic demonstrations in support of Galtieri.
A proposal to promote Galtieri to the newly created rank of First Marshal of the Empire initially received broad public support.

Galtieri and most of his government mistakenly believed the UK would not respond militarily and that the United States would not interfere.

The British government led by the prime minister, Margaret Thatcher, determined to overturn the invasion.
It dispatched a seaborne task force to drive the Argentinian forces from the islands, resulting in the Falklands War and an Argentinian surrender on 14 June 1982.
In April 1982, Galtieri had been in office for four months and his popularity was low. On 2 April, and on his orders, Argentine forces invaded the Falkland Islands, a United Kingdom territory subject to a long-standing Argentine claim. 
Initially the invasion was popular in Argentina, and the anti-junta demonstrations were replaced by patriotic demonstrations in support of Galtieri. A proposal to promote Galtieri to the newly created rank of First Marshal of the Empire initially received broad public support. 
Galtieri and most of his government mistakenly believed the UK would not respond militarily and that the United States would not interfere.
The British government led by the prime minister, Margaret Thatcher, determined to overturn the invasion. It dispatched a seaborne task force to drive the Argentinian forces from the islands, resulting in the Falklands War and an Argentinian surrender on 14 June 1982.
Leopoldo Galtieri