With all due respect to Mitch McConnell, Republicans shouldn’t even be talking about a gun-control deal unless that deal includes doing something about the fundamental problem: The utter refusal of the federal government and most Democrat-run states and counties to prosecute ordinary, common gun crimes.

Take any example you like: In Philadelphia, the majority of gun cases — 60 percent — are simply dismissed with no prosecution, according to the local district attorney’s office. That’s double the dismissal rate of 2016 — and the district attorney is bragging about how few gun crimes get prosecuted.

Straw-buyer cases are almost never prosecuted unless they are part of a big organized-crime investigation. “Lie and try” cases — in which prohibited buyers attempt, often successfully, to beat the background-check system — are almost never prosecuted at all, which is why Hunter Biden is not in prison on federal gun charges. Possession cases are routinely dismissed without prosecution. In Illinois, the clearance rate for gun crimes short of murder is a measly 33 percent — meaning that two-thirds of cases go unresolved. A third of the murderers in Baltimore are already on probation or parole for another crime. Etc.