It was the most murderous gun rampage in U.S. history: 32 people dead, more than a dozen injured. A senseless, barbaric act that the whole country watched in stunned disbelief. We heard the gunshots in Norris Hall. We saw the panic in the faces of fleeing students. And, as details emerged, we asked a basic question: how could we allow a mentally ill person to buy guns? Federal law prohibited the shooter, Seung-Hui Cho, from buying guns. But his mental-health records were not in the government’s database, so he passed his background check. With the public demanding that this gap in the background-check system be closed, that December Congress passed the nation’s first new gun law since 1996. Will it stop the next massacre? Probably not, because an even bigger loophole still exists: the mentally ill and criminals can avoid background checks entirely, simply by going to gun shows. That’s a big reason why our country experiences a Virginia Tech-size massacre every day of the year: 34 Americans are murdered with guns daily. And like Cho, most of the murderers possess their guns illegally. Some of the family members of the Virginia Tech victims have since become powerful voices in the effort to close the gun-show loophole, reminding Congress that keeping guns from criminals and the mentally ill has nothing to do with the Second Amendment. Will Congress listen? Only time will tell. But the Virginia Tech victims have, in death, breathed new life into legislation that could save thousands of others.