The 2020 presidential election might be the first to hinge on gun control

When is the right time to have a meaningful, substantive debate on gun control? 

The correct answer, of course, is “yesterday.” For Republican lawmakers, the answer is “never.” For the field of Democrats running for president, the answer might finally be “now.”

It’s taken a few years — a few decades, perhaps — longer than one would hope, but Democrats in Congress and on the campaign trail are beginning to find their voice on the issue of gun control.

As recently as a f...