Justices aligned with Mexico’s leftist governing party now dominate the Supreme Court. Party loyalists control a new tribunal with the power to fire judges and the court that decides federal election disputes.

Leaders of the Morena party, which already holds the presidency and Congress, had insisted that their contentious judicial overhaul, among the most far-reaching ever tried by a large democracy, would not be a power grab. On the contrary, they said, it would make judges accountable to voters and begin to fix a system that most Mexicans say is marred by corruption, nepotism and widespread impunity for criminals.

But Mexico’s shift away from an appointment-based system to having voters elect judges has, at least for now, amounted to a crucial step in Morena’s consolidation of power, according to election results made available on Sunday.

Candidates with Morena’s stamp of approval sailed to victories in Mexico’s most powerful courts and in court circuits across the country, showcasing critics’ fears that the election could eliminate the last major check on Morena’s power.

“You now have an administration that controls the presidency, that controls the Congress with supermajorities in both chambers and that now controls the judges,” said María Emilia Molina, a circuit magistrate and president of the Mexican Association of Women Judges.

She and 13 other judges have challenged the overhaul through an international human rights commission, filing a case that contends that it violates judicial independence and the rights of sitting judges.