After becoming president, Alfonsín sent a bill to Congress to revoke the self-amnesty law established by the military. He established the National Commission on the Disappearance of Persons to investigate the crimes committed by the military, which led to the Trial of the Juntas and resulted in the sentencing of the heads of the former regime. Discontent within the military led to the mutinies of the "Carapintadas", leading him to appease them with the full stop law and the law of Due Obedience. He also had conflicts with the unions, which were controlled by the opposing Justicialist Party. He resolved the Beagle conflict, increased trade with Brazil, and proposed the creation of the Contadora support group to mediate between the United States and Nicaragua. He passed the first divorce law of Argentina. He initiated the Austral plan to improve the national economy, but that plan, as well as the Spring plan, failed. The resulting hyperinflation and riots led to his party's defeat in the 1989 presidential elections, which was won by Peronist Carlos Menem.