But the criticism is worrisome. Mexico is ranked one of the deadliest countries for journalists. Six have been murdered since AMLO’s inauguration on Dec. 1. At least 124 people have died in connection with their work since 2000, according to the organization Article 19. In a country wracked by violence related to drug trafficking, journalists fall as if they were in a war zone. The president can and must do much more to protect my brave colleagues.

The primary social responsibility of journalists is to question those in power. It is up to us to serve as a critical counter-power and to ask difficult questions. But Mr. L ó pez Obrador doesn’t seem to understand this. He recently praised those journalists he deemed “prudent,” and declared: “If you cross the line, well, you know what happens, right? But it’s not me it’s the people.”

Indeed the wild jungle of social media can be brutal in the face of criticism of Mr. López Obrador. He is a very powerful president — he controls Congress — and won the presidency thanks in part to a wide popular social support. More than 30 million people voted for him in a nation mired in violence and corruption. After Enrique Peña Nieto’s disastrous presidency, it’s understandable that Mr. López Obrador has managed to garner people’s hopes for change. Particularly among the most vulnerable Mexicans.

But that doesn’t mean that AMLO is untouchable. It would be grievous for Mexico to resuscitate some of the practices of the period from 1929 to 2000, when presidents dictated what could and could not be published. And the only way to avoid that is by being irreverent and disobedient toward authority. It’s not a lack of respect; it’s the way in which vigorous and independent journalism is done. The president is not our boss. As journalists, we are accountable to our readers, viewers, and listeners, and above all, to the truth. In the end, it’s a simple matter of credibility. And credibility is not achieved by being close to power, or by praising it. He must develop a thicker skin.

Mr. López Obrador was out of line when he asked the Mexican newspaper Reforma to reveal its sources. Reforma published the text of a private letter that the Mexican president sent to the king of Spain requesting his apology for the abuses and grievances committed during the conquest. Asking for the disclosure of journalistic sources, I told AMLO at the Mañanera on Friday, is an attack on press freedom. “No journalist, Mr. President, will reveal their sources. None.” He didn’t agree, but he hasn’t followed up on his request to the newspaper.