Mexico’s president lashed out Wednesday at the chief justice of the country’s Supreme Court, accusing her of promoting rulings favorable to criminal suspects.

President Andrés Manuel López Obrador’s comments opened a new debate over the separation of powers in Mexico, at a time when the Supreme Court is expected to rule on the president’s controversial cuts to election agency funding.

López Obrador has already attacked independent regulatory agencies, slammed the judiciary and cut funding for the National Electoral Institute.

The electoral dispute has led the president to feud with the press, demonstrators and the U.S. State Department. Opponents say the electoral cuts threaten Mexico’s democracy, and have appealed them to the Supreme Court.

López Obrador’s comments Wednesday opened a head-on conflict between the administration and Supreme Court Chief Justice Norma Piña, the first woman to hold that post.

The president was angered after a judge issued an injunction striking down an arrest warrant against Francisco Garcia Cabeza de Vaca, a former governor of the northern border state of Tamaulipas, who had been accused of corruption.