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Maybe this time will be different. That's the thought on the minds of many Americans now.

Two mass shootings in 24 hours have left at least 29 people murdered and many dozens more wounded. This, just a few days after a shooter at a festival in California killed three and wounded a dozen — with shooting sprees in Brooklyn, Chicago and Mississippi that also left people dead, dozens wounded and communities shaken.

President Donald Trump addressed the nation Monday but failed to mention the two most important words in this debate: background checks. While he said he supports a federal red-flag law, which allows law enforcement to remove guns from those who pose serious mental-health risks, he has yet to push for it. And he pinned more blame on video games and the internet than on our laws that enable such horrific violence — the usual dodge.

And so a familiar ritual threatens to repeat. Politicians express sympathy for the victims, hint at openness to insufficient actions, then run out the clock as public attention moves elsewhere. It's an appalling cycle of political malfeasance that is in danger of recurring even now — after a weekend in which a man in El Paso murdered 20 and wounded dozens, and the very next day a shooter in Dayton killed at least nine and wounded at least 26.

This mustn't be allowed to happen. These new atrocities need to change the political dynamic. U.S. Sen. Lindsey Graham stated on Saturday: "Time to do more than pray. Time to enact common-sense legislation in Congress to empower states to deal with those who present a danger to themselves and others — while respecting robust due process."

He's right — only it's past time. And it's not enough.

I spent last Friday morning with thousands of volunteers from Moms Demand Action and Students Demand Action. They had come to Washington to do exactly that: Demand action.

Over the past few years, millions of Americans have joined together to push for common-sense legislation — and it's working.

From Connecticut and Florida to Colorado and California, states have made strides on gun-safety legislation, especially when it comes to red-flag laws that deny guns to dangerous people. But state lines are porous: The shooter at the festival in California got his gun in Nevada. For common-sense reform to move forward everywhere, America's post-massacre ritual has to stop. The anger must be sustained and channeled into political action — as it was in last year's midterm elections, when volunteers from groups like Moms Demand Action elected dozens of gun-safety proponents to the House of Representatives.

For too long, too many states — along with Washington — have bowed to the demands of the gun lobby, which pretends that reasonable gun regulation that is proven to save lives is incompatible with the Second Amendment, even though the Supreme Court, in a majority opinion authored by Justice Antonin Scalia, found otherwise.

The Second Amendment isn't the problem. The problem is that the National Rifle Association doesn't advocate for gun owners, the vast majority of whom support common-sense gun-safety laws. It represents and is financed by an industry bent on selling as many guns to as many people as possible.

The two states where the most recent tragedies occurred are examples of this. Both Texas and Ohio have gun laws endorsed by the gun lobby. These are excellent laws if your only aim is to sell guns to anyone. They do little to restrict purchases by the enraged and unhinged, while also encouraging residents to carry guns everywhere out of fear that the enraged and unhinged will turn their arms on them.

Instead of sensibly regulating gun purchases and possession, Texas and other gun-lobby protectorates have outsourced their responsibilities to the "good guy with a gun." Yet time and again, people are shot before the good guy, who in reality almost always wears a badge, can stop the carnage. Ohio law-enforcement officers encountered the Dayton shooter within a minute. It was too late. There are countless cases of accidental shootings, rage-induced homicides and alcohol-fueled attacks for each instance of an armed civilian stopping a shooting. A recent Federal Bureau of Investigation report gives zero credence to the good-guy-with-a-gun myth.

Until the superheroes turn up, laws will have to do. The House of Representatives passed a hugely popular comprehensive background-check bill in February, along with legislation to close the loophole that let a racist mass murderer acquire the weapon he used in a church in Charleston, South Carolina, in 2015.

Senate Republicans have failed to act on both those proposals. That will change only if more Americans demand it — and send a clear message to their representatives that voting against gun safety will cost them on Election Day.

This time can be different. But only if we reward political leaders who protect public safety, and drive those who don't from public office. We cannot let this moment pass.

Michael R. Bloomberg, the former mayor of New York City, is the founder and majority owner of Bloomberg LP, the parent company of Bloomberg News. He is the U.N. secretary-general's special envoy for climate action.