The Argentine Armed Forces was and still is considered one of the prime military forces of Latin America.
The Argentine military was descended from the militia forces that defeated two British invasions prior to gaining independence from Spain. The same colonial militias formed the backbone of the independence armies that later liberated Argentina in its War of Independence in the 1810s. The Argentine military also distinguished itself in wars against Brazil and on one occasion against Paraguay in the middle of the 19th century.
However, the Argentine military became infamous as it also got the habit of setting up military dictatorships, in one of which Colonel Juan Domingo Peron (of Evita fame) participated. He would then go on to be democratically elected as President three times. The military was also responsible with the 1976-1983 regime and in what was called the "Dirty War", which caused the deaths of 30,000 Argentineans.
The Argentine Armed Forces, however, became most infamous in the Falklands (or Malvinas) War against Britain in 1982. Although the Argentine military initially held the initiative, the British eventually defeated the Argentines, causing the military to get out of politics for good in 1983. Since then, its confined itself to peacekeeping missions. In the Gulf War, Argentina was the sole Latin American country to send a military contingent.
Service in the military was compulsory, until the murder of a conscript in 1994 prompted the change to voluntary service. It is a non-NATO major ally of the US and has cooperated with the militaries, of all nations, their longtime rivals Brazil and Chile; it perhaps did lessen the tension between these countries. In football, of course, that was another story.