MEXICO CITY (AP) — Mexicans were voting Sunday in a potentially transformative election that could put in power a firebrand vowing to end politics and business as usual in a country weary of spiraling violence and scandal-plagued politicians.

Front-running candidate Andres Manuel Lopez Obrador was one of the first lined up to vote at his polling place in Mexico City, and some of his supporters turned out early.

"There is a lot of inequality, a lot of violence in this country," said Lopez Obrador voter Hugo Carlos, 73. "This situation has to be changed."

While Lopez Obrador held a commanding le...