STORY: Organizers said over 500,000 people turned out in Mexico City, with protesters filling the central Zocalo square.

Mexico's Congress on Wednesday approved a major overhaul of the National Electoral Institute (INE), an independent body which Lopez Obrador has attacked as corrupt and inefficient.

The 69-year-old president denies his changes will weaken Mexican democracy. Critics have vowed to take the legislation, which slashes the INE's budget and staff as well as paring back its responsibilities, to the Supreme Court.

Former Supreme Court Justice, Jose Ramon Cossio, addressed the crowd in Zocalo square saying; "We want to tell the (Supreme Court) justices, as we stand before the building where they work, that we trust them. That we trust their democratic attitude and their capacity to understand the importance of the decision they will make to preserve the country’s democratic life.”

Lopez Obrador, a leftist who contends he was robbed of the presidency twice before he finally romped to a crushing victory in the 2018 election, argues the INE is too expensive and biased in favor of his opponents. The institute denies this.

The president has cast Sunday's protests as a partisan attempt by the opposition to discredit his government.