Mexico is experiencing one of the deadliest periods on record for journalists, with five killed so far this year. But instead of addressing these dangers, President Andrés Manuel López Obrador devoted much of his regular news conference on Friday to attacking one of the country’s most prominent media figures, Carlos Loret de Mola.

Mr. Loret de Mola, a contributing columnist for The Washington Post’s Spanish-language Post Opinión section, is a household name in Mexico, reporting for print, radio and television. A frequent critic of the government, he recently released an investigation into Mr. López Obrador’s son, whose apparently lavish lifestyle stands in dramatic contrast to the Mexican president’s down-to-earth public persona.

On Friday, in a brazen attempt to discredit and intimidate an independent voice, Mr. López Obrador presented a slide purporting to show Mr. Loret de Mola’s income in 2021. He claimed it was “15 times” more than the president’s salary, though Mr. Loret de Mola says the amounts presented were false and that he hasn’t worked for at least one of the organizations listed since 2019. The public sharing of a citizen’s confidential financial information is an unprecedented abuse of power. Mr. López Obrador has also threatened to ask tax authorities to confirm this information, which would violate Mexico’s privacy laws.

Mr. López Obrador renewed the attacks Monday, calling those who publish critical articles “thugs, mercenaries [and] sellouts.” The episode marks a new low in his fraught relationship with the media. He has often complained about critical reporting, calling himself “the most attacked president in the last 100 years.” His most recent tirade only emboldens those who attack journalists amid a surge of violence against reporters and whistleblowers — most of whom are not as well known as Mr. Loret de Mola.

Just hours before the news conference, reporter Heber López Vásquez was shot and killed outside his house in Oaxaca. Lourdes Maldonado López — who in 2019 told Mr. López Obrador that she feared for her life — was shot dead in a car in Tijuana last month. Reporter José Luis Gamboa, photojournalist Margarito Martínez and camera operator Roberto Toledo were also killed in January.

Even before this year, Mexico was one of the most dangerous countries in the world for journalists, with at least seven killed in 2021 and 15 currently reported missing. Most of the attacks on media workers stem from municipal authorities and organized crime, according to government data. Mr. López Obrador’s administration has expanded the country’s press-protection program, but rights groups and journalists say criminals can still commit acts of violence with impunity.

The escalating violence is a stain on Mexico’s democratic record. The Biden administration last year committed to “protecting and promoting free, independent, and diverse media around the world.” It should condemn the attacks on Mexican journalists and call for our democratic allies to support a free press. If they don’t, rogue regimes and bad actors will continue to act as though they have a free hand in their escalating efforts to silence independent voices.