No, Mr. Trump. Guns are the reason for mass shootings.

FOR A moment on Monday, President Trump offered a teasing hope that he would jolt the Republican Party into easing its roadblock on even the most obvious and popular gun-control measures. Following a grisly weekend of mass shootings, Mr. Trump tweeted in favor of “strong background checks” so that “something good, if not GREAT, [comes] out of these two tragic events!”

Soon enough, the president subsided to form. He read a speech that focused on mental health issues, violent video games and the Internet as major factors in the nation’s increasingly bloody culture of gun violence. “Mental illness and hatred pulls the trigger. Not the gun,” he said.

But mental illness and hatred exist throughout the world, as do video games. Frequent mass shootings are unique to the United States. The reason is guns, and especially semiautomatics. Unique to the United States is easy access to the means to commit mass murder.

Congress has improved mental health policies in recent years. Research shows little connection between violence found in video games and in the real world. And while the Internet can accelerate the spread of extremism, it does not create extremism. More might be done in all these areas. But the crucial variable is access to guns.

Mr. Trump did restate his support for one gun-related measure, so-called red-flag laws that would allow judges to order the temporary confiscation of firearms from people who present imminent threats to themselves or others. If the president actually lobbied the GOP to follow through on this, it would be a good step. Though pro-gun groups decry such measures as avenues for weapon confiscation without due process, judges make the final call based on evidence of substantial threat. States that have enacted red-flag laws recently have seen notable progress on preventing suicide. At least one mass shooting appears to have been prevented because of a red-flag statute.

But Mr. Trump has a history of talking a big game on basic gun control, only to fail to follow through. And even if he surprises in this case, a new red-flag law would not be nearly enough. The president’s apparent first instinct to tighten federal background checks was right. All firearms sales and transfers should be subject to checks — not just some, as is currently the case. The loophole that allowed the Charleston, S.C., church shooter to obtain weapons should be closed. And high-capacity magazines such as those used in this past weekend’s mass shootings, which allow shooters to mow down victims without breaking to reload, should be banned. Yet, as the House has passed bills to do such things, the Trump administration has signaled opposition, and the Republican Senate appears uninterested.

No amount of talk about video games can distract from the fact that the nation’s gun laws are a major, deadly problem. No amount of sympathy for mass shooting victims will change the fact that the country’s cowardly Republican leaders are failing to address it.