The laws on background checks for gun sales are not as lax as critics say, or as many people assume. But the law does not require all gun buyers to undergo checks.

In 32 of the 50 states, private citizens who do not make a living in the gun trade may legally sell firearms to persons living in the same state without background checks.

All other legal sales require checks, and that means the vast majority are covered. It is also illegal under current law to buy a gun for someone else to help them evade a background check, as a neighbor allegedly did for the San Bernardino shooter.

It is important to understand two things about background checks on private, intrastate sales. One is that the current lack of them is hardly ever the reason mass killings take place. A New York Times study highlighting how weapons were acquired in 15 recent high-profile mass shootings did not find a single one acquired through a legal private sale where no background check was required.

Even so, it is important that gun rights supporters do not reflexively dismiss the potential danger in private sales that are not checked. The proper identification and treatment of mentally ill people should certainly be a higher priority than background checks on gun sales, but by the same token, efforts to identify mental illness will be far less helpful if sellers are not checking buyers.

At a time when prominent politicians are backing universal gun confiscation, and the Second Amendment is otherwise under assault, it is not surprising that gun owners are wary of expanding background checks. Moreover, the checks are an intrusive hassle and expensive as currently conducted. Only federally licensed dealers have access to the National Instant Criminal Background Check (NICS) system, and they charge buyers to run checks and to handle weapons in private sales. This means the process also takes more time. This all deters sellers from insisting on a background check where it is not legally required.

Yet no law-abiding gun owner wants to sell a gun to a mad man who will use it to murder children in their school or workers at their office. Gun owners would be grateful if they were given the ability to check buyers for themselves. And indeed, a solution is at hand. There is a way for the federal government to make it easy to do the right thing. If it did, a much larger proportion of sales and buyers would be checked.

After the Sandy Hook massacre, Sen. Tom Coburn, R-Okla., proposed an instant check system that anyone could use free online, rather like booking an airline ticket.

Would-be buyers could go online, enter their personal information as if they were checking their credit score and run a background check on themselves. If they passed, the system would give them a tracking number, good for 30 days, that they could present to a seller. The seller could then enter the tracking number online and verify that the buyer was legit. (The seller would not get access to the buyer's personal information, just to whether he passed the check.)

Gun-control advocates objected to Coburn's proposal because this entire system was voluntary. But from their perspective, this is still far better than the status quo, as it would overnight result in far more private legal gun transactions being checked.

Gun owners would finally have the information they needed, available for free, to prevent hundreds or thousands of annual sales to known criminals and mental patients. And it might only take one such non-sale to prevent a tragedy.

The Coburn proposal would also immediately improve compliance with existing state and federal laws where background checks are already mandatory. Facing neither the hassle, nor the expense, nor the outright refusal by some gun dealers to conduct checks for private sales, gun sellers of good will would be far less likely to take a chance on an unknown buyer.

Most importantly, due to its voluntary nature, this proposal would stand a real chance of passage, perhaps even with strong support from gun owners. Most people, after all, want to do the right thing. As Coburn put it, "If you make it easy for people to comply with the law, they'll do it."

Like the current laws, and like other proposals such as expanded mandatory NICS checks, this is not a panacea. It would not stop mass shootings in which the guns doing the killing are stolen (as in Sandy Hook), obtained through straw buyers (as some were in San Bernardino), purchased by people who can pass background checks or purchased from illegal black market arms dealers.

But the Coburn system would start doing good from day one, and it doesn't introduce the element of government control that typically drives gun owners to thwart such measures.

This proposal should be resurrected in tandem with the more urgent and important measure that will make background checks work better — the improvement of the identification and treatment of severe mental illness.