A victim is carried away from the scene of Wednesday’s mass shooting in San Bernardino, Calif. (David Bauman/The Press-Enterprise via Associated Press)

THE THREE people mercilessly gunned down in Colorado Springs had not even been buried when Americans again found themselves reeling from another mass shooting. More dead, more wounded. More grieving families.

Wednesday’s events in San Bernardino, Calif. , brought into tragic relief the dangers facing this country from within and without and the need for strategies to prevent the people — whether they are terrorists, mentally ill, or both, or neither — from being able to do harm. Many factors come into play, but as we’ve said before, one factor is common to every mass shooting: guns.

The scenes that played out Wednesday were depressingly familiar to a country where mass shootings occur on average more than once a day. News alerts about an “active shooter” situation, followed by images of heavily armed police tactical teams swarming the scene, paramedics tending the wounded, shell-shocked accounts from survivors — and then the casualty list. In the latest case, 14 people were killed when two shooters — reportedly a husband and wife later killed in a gunfight with police — stormed a holiday office party. An additional 21 were injured. It was the deadliest mass shooting in the United States since the slaughter of schoolchildren at Sandy Hook Elementary three years ago.

The FBI announced Thursday it was taking over the investigation into suspects Syed Rizwan Farook, 28, and Tashfeen Malik, 27, because of possible links to international terrorism. Unnamed law enforcement officials cited indications that the couple had been in contact with people with Islamist extremist views, here and abroad. The nature of the attack suggested it was planned, but the search for a motive also centered on a dispute Mr. Farook had with co-workers at the holiday party before he returned, masked and with guns.

Among those weapons were .223-caliber assault rifles and semiautomatic handguns. Federal authorities said the weapons were purchased legally. Why are weapons designed for war — the .223-caliber is described as powerful enough to pierce the standard protective vest worn by police officers — even on the market? That is one question that should be posed in the aftermath of this shooting. To do so, though, would require those in Congress and state legislatures to acknowledge that there are steps they could take that would save lives: stricter requirements about who can own guns, technology to improve safety, research into gun violence.

The Dec. 2, San Bernardino, Calif., shooting brought the number of U.S. mass shootings to 355 this year. Here's how the FBI defines a mass shooting and how it's different from a mass killing or a massacre. (Gillian Brockell and Monica Akhtar/The Washington Post)

Yes, the nation needs to pursue Islamist terrorists overseas more aggressively and combat radicalization at home. Yes, we need to offer better mental-health treatment. But we also need to make it more difficult for civilians to obtain weapons of war. Only one day before the San Bernardino shooting, members of Congress observed a moment of silence for the victims of the Colorado mass shooting. Unfortunately, that silence is the most they’ve been able to offer so far.