Senator Alejandro "Alito" Moreno, who leads the opposition Institutional Revolutionary Party (PRI), was apparently incensed over the refusal of his demands to participate in the floor debate, which featured accusations that PRI and the National Action Party (PAN) had called for the US military to strike the cartels inside Mexico -- which both parties deny.

Earlier this month, President Trump reportedly issued a new directive authorizing the Pentagon to conduct direct military operations against select Latin American drug cartels designated as Foreign Terrorist Organizations (FTOs). Last week, PAN member Lilly Tellez told Fox News, that "help from the United States to fight the cartels is absolutely welcome, and that is how the majority of Mexicans feel. The only ones who don't like that President Trump is sending help...are the narco-politicians, and that includes President [Claudia] Scheinbaum."  

Tellez compounded the tension in Wednesday's debate, saying she had "a clean record," unlike what she labelled "the Morena mafia." She condemned members of the ruling Morena party as "narcopoliticians" and "narco-Satanics," and credited her faith in God and Mexicans for giving her the resolve to "make the Morenarcos tremble." Her barbs prompted shouts of "sellout" and "traitor." 

As the session was ending, the 50-year-old Moreno strode to the podium and accosted 65-year-old Senate President Gerardo Fernandez Norona, of the Morena party. Along with the rest of the Senate, Norona was singing the national anthem, in accordance with the custom for closing out sessions, but Moreno continued shouting at him. After the anthem ended, Norona turned to talk to Moreno, and the ensuing shouting match grew violent after Moreno grabbed Noreno's arm. 

As the two engaged in a shoving match, a cameraman stepped in front of Moreno, and was greeted with a firm, two-armed shove that sent him to the floor. Another man proceeded to pummel the cameraman on the ground, and Moreno's fellow PRI member, Carlos Gutiérrez Mancilla, pursued the Senate president out of the hall, grabbing him by the suit-jacket and punching him. El Pais reports that the cameraman was injured, with medics putting him in a neck brace. 

"What confrontation? He hit me and said, 'I'm going to kill you'," Norona told reporters later. Chumming the waters, Norona added, "Today, when (opposition legislators) are exposed for their treason, they lose their minds because they were exposed." Norona said he would pursue an emergency Friday session to expel Moreno and three other PRI legislators. He also said he will file a complaint against Moreno for attacking him and the cameraman, and ask authorities to revoke Moreno's legislative immunity.