On Sunday, Mexicans head to the polls to elect a new president, 500 members of Congress and 128 senators amid mounting discontent over rampant corruption and increasing violence.
: Front-runner with a substantial lead in the polls. He is the former mayor of Mexico City and the leader of the leftist National Regeneration Movement.
: A conservative representing the National Action Party, which ruled Mexico for 12 years before it was ousted from power by the election of current President Enrique Pena Nieto. He trails Obrador in the polls.
: The candidate of the ruling International Revolutionary Party (PRI), which is as unpopular as its current leader, the president.
Polling in single digits, independent candidate Jaime Rodriguez currently ranks last in polls.
— Nearly 90 million Mexicans are eligible to vote.
— Plurality of votes determines the winner. There are no runoffs.
— Winning candidate will be sworn in on December 1.
: Mexico has seen a huge spike in violence, especially against politicians and journalists. More than 500 politicians have been attacked since campaigning began last September. At least 130 have been killed.
Government statistics show there have already been more than 20,000 homicides so far this year.
Long a problem in Mexico, corruption has soared under the presidency of Pena Nieto. A number of senior lawmakers and even the first lady have been involved in high-profile graft cases.
: Tensions with U.S. President Donald Trump have emerged as an election issue. The renegotiating of the North American Free Trade Agreement, the border wall, U.S. tariffs on Mexican goods and the "zero tolerance" immigration policy are all in play.