Prior to the military coup in 1968, Peru was governed under the constitution of 1933, which declared Peru to be a republic with a centralized form of government. Legislative powers were vested in a Senate and a Chamber of Deputies, of variable number. Both senators and deputies served their electoral districts for a period of six years. Under the constitution, executive power was held by the president, who, with two vice presidents, was elected for a six-year term, with a minimum of one-third of the vote, but could not be reelected until an intervening term had passed. Voting was obligatory for all literate Peruvian citizens aged 21 to 60.
The military leaders who seized control of the government in 1968 immediately disbanded the bicameral Congress. For the following decade, Peru was ruled by a military junta consisting of the president and the commanders of the three armed forces. The return to civilian rule began with the election of a Constituent Assembly in June 1978 and the promulgation of a new constitution on 12 July 1979. Presidential elections were held in May 1980, and Peru's first civilian government in 12 years took office in July.
After the autogolpe in 1992, the constitution was suspended. A new Constituent Assembly was elected and a new constitution was written. For the most part, all the major elements of the 1979 constitution were preserved, but presidents were allowed to run for one immediate re-election. Under the 1979 constitution, the president was popularly elected for a five-year term and could not be reelected to a consecutive term. The winning candidate had to win at least 50% of the vote or face a runoff election against the second-place candidate. The National Congress consisted of a 60-member Senate and a 180-member Chamber of Deputies. All elected legislators had five-year terms. The 1979 constitution eliminated literacy as a qualification for voting and made suffrage universal at age 18.
The current Congress is unicameral, consisting of 120 elected members elected for five year terms by proportional representation.