Outside Mexico’s Senate building on Tuesday, university students wearing masks and dressed as the country’s Supreme Court justices took turns smashing a black piñata with a stick. The piñata, covered in the word “justicia,” or justice, was filled with fake money — a performance staged to illustrate the supposed corruption plaguing the country’s judiciary.

“The election of judges and magistrates by popular vote is a democratization of one of the most important powers of our country,” said Layla Manilla, 21, one of the participating students, who is studying politics.

Ms. Manilla is one of thousands of Mexicans who have taken to the streets in recent weeks to show their support for — or opposition to — the contentious judicial overhaul championed by President Andrés Manuel López Obrador and his allies, which on Wednesday overcame its last major obstacle when it was narrowly passed in the Senate.

In interviews with The New York Times, Mexicans expressed a range of concerns and aspirations for the measure. Some worried about the end of judicial independence, while others celebrated the chance to vote in the people responsible for distributing justice. Many more were indifferent to the overhaul, unclear on exactly what to expect from the change.

The legislation would shift the judiciary from an appointment-based system, largely grounded in training and qualifications, to one in which voters elect judges and there are fewer requirements to serve. Some 7,000 judges would lose their jobs, from the chief justice of the Supreme Court down to those at state and local courts, and Mexicans could start voting as soon as next year.