General elections are scheduled to be held in Mexico on 1 July 2018. Voters will elect a new president to serve a six-year term, 500 members of the Chamber of Deputies and 128 members of the Senate. The members of the legislature elected on this date will be the first allowed to run for re-election in subsequent elections.
Incumbent president Enrique Peña Nieto is not eligible for a second term according to Mexico’s constitution.
The country’s president is elected by plurality in a single round of voting.
The 500 members of the Chamber of Deputies are elected by two methods; 300 are elected in single-member constituencies by first-past-the-post voting, with the remaining 200 elected in a single nationwide constituency by proportional representation, with seats allocated using the simple quotient and largest remainder method. No party is allowed to hold more than 300 seats.
The 128 members of the Senate are also elected by two methods, with 96 elected in 32 three-seat constituencies based on the states and 32 elected in a single nationwide constituency by proportional representation. In the three-seat constituencies two seats are allocated to the party receiving the highest number of votes and one seat to the party receiving the second-highest number of votes.
Sources and Further Reading:
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