The rote responses of most congressional Republicans to the murder Tuesday of 19 Texas schoolchildren and two of their teachers were so wrenchingly vapid, so grotesquely lacking in any sense of urgency, that Representative Ruben Gallego could not take it any longer. The Arizona Democrat read a statement from Republican Senator Ted Cruz in which the Texan claimed those who demanded action to avert future school shootings were “politicizing” the tragedy. And he responded appropriately.

“Fuck you @tedcruz you care about a fetus but you will let our children get slaughtered,” replied Gallego. “Just get your ass to Cancun. You are useless.”

In case anyone missed the point, Gallego came back a few minutes later with an even blunter message on Twitter: “Just to be clear fuck you @tedcruz you fucking baby killer.”

Gallego’s honest fury was refreshing, and he undoubtedly spoke for a good many of the tens of millions of Americans who are enraged by Republican obstruction of action on gun control and a host of other vital matters, including the future of a democracy that is profoundly threatened by Donald Trump’s partisan allies. Yet Gallego’s frustration did not end there. The congressman ripped into a fellow Democrat from his own state, Senator Kyrsten Sinema, who has joined with West Virginia Democrat Joe Manchin to block filibuster reforms that would allow Democrats to use their majorities to advance popular gun-control measures.

Sinema issued a statement that echoed the Republican line. While she said she was “horrified and heartbroken by the senseless tragedy unfolding at Robb Elementary School in Texas,” the senator gave no indication that she was prepared to do anything to end the horror and heartbreak.

“Please just stop,” responded Gallego, “unless you are willing to break the filibuster to actually pass sensible gun control measures you might as well just say ‘thoughts and prayers.’”

Gallego’s anger was understandable. He gave voice to the intense frustration that most Americans feel with politicians who have mastered the art of sounding empathetic while saying nothing of consequence.

But his response also raises a troublesome question: Is there anything that responsible members of Congress who are not in the service of the National Rifle Association and the gun-manufacturing industry can do to counter those members from both parties who are, as President Biden noted in a poignant speech Tuesday evening, “willing to live with this carnage”?

There is something that Gallego can and should do.

The congressman—a veteran and father of a young son who has for many years been an outspoken advocate for gun control measures—should end the speculation about whether he will mount a primary challenge to Sinema in 2024. He should make the run.

Ever since March of 2021, when Sinema gave a snarky thumbs-down to a proposal to raise the minimum wage to $15 an hour, anger with the senator has been mounting among Democrats in her home state. That anger reached a boiling point last fall, when Sinema and Manchin stalled progress on President Biden’s Build Back Better agenda. “Grassroots groups, advocacy organizations, unions, etc. will not work for her and will work against her,” declared Garrick McFadden, a former vice chair of the Arizona Democratic Party. “She has betrayed her friends and the promise she made to the Arizona people. She wants to play games, well in 2023 we start playing games with her.”

Groups such as the Primary Sinema Project have raised hundreds of thousands of dollars to support a challenge, and grassroots organizers such as Arizonan Kai Newkirk, founder of the Sinema Primary Pledge campaign, have organized vigils, rallies, and protests to call out the state’s senior senator.

What the critics of Sinema need is a candidate with the experience and stature to beat the senator in a 2024 primary. There’s a lot of sentiment that says Gallego is that candidate.

Last fall, Nuestro PAC, a group launched by Chuck Rocha, initiated a “Run Ruben Run” campaign to recruit the congressman to run. Not long after, Rocha, who played a pivotal role in organizing support among Latino voters for the 2020 presidential campaign of Senator Bernie Sanders, announced that the effort had received $1 million in commitments. Senior Democrats recognized why there was so much enthusiasm for Gallego. “Ruben is a strong progressive leader who has accomplished a lot of things in a short time,” said former Maricopa County (Phoenix) Democratic Party chair Steven Slugocki. “He’s passed a lot of bills, he’s a veteran, he’s a Latino. He’s a strong voice in Congress who’s getting things done. He has a lot of support in the party as well as with Democrats across the state.”

For his part, Gallego has criticized Sinema by name in his speeches. He has described her approach as “deeply disappointing.” He does not dismiss the prospect of mounting a primary challenge. But he does suggest that he is focused for the time being on his own reelection bid this fall—which he will win easily in a very Democratic district—and on electing Arizona Democrats such as gubernatorial candidate Katie Hobbs and US Senator Mark Kelly.

That may delay a formal announcement for a time. But it should not delay a decision on the part of Gallego to take on Sinema.

The damage Sinema has done to the Democratic agenda, especially when it comes to fighting gun violence, demands more than criticism, however blunt. Her actions require a primary challenge that is sufficient to replace her with a Democrat who can hold the seat in 2024.

Gallego’s clarity with regard to gun violence, and with regard to Sinema’s obstruction of congressional action to address that violence, confirms that he is the best prospect to mount that challenge.