When federal law doesn’t go far enough to prevent weapons from being sold to convicted felons and people who are psychotic or suffer from certain mental illnesses, it’s a problem for everyone.

We’re not talking about restricting law-abiding people from possessing firearms, used for hunting, target practice or personal protection. We’re talking about the fact that in certain circumstances a lack of oversight enables people who could be a danger to themselves or others — and for whom it’s already illegal to buy guns — to buy guns.

If people purchasing firearms at licensed gun stores are required to undergo background checks, people purchasing firearms online, at gun shows, out of someone’s home or at a flea market should also be required to undergo background checks. It’s a matter of safety and consistency.

The demonic shooting at a movie theater in Aurora, Colo., which killed 12 people, brings up the larger issue of how to best protect people while not infringing on Second Amendment rights. The arrest of a Biddeford man on Sunday, who told police he brought a loaded gun to a Saco showing of “Batman: The Dark Knight Rises,” brings the matter even closer to home.

It’s undeniable that requiring background checks will not prevent every tragedy. But it should not be convenient for people to be able to purchase firearms illegally. Background checks should be provided instantly or as soon as reasonably possible.

It is illegal for anyone to sell firearms to people who they know are prohibited from purchasing them. That’s why it doesn’t make sense that private gun dealers don’t have to verify the background of a customer, while licensed gun dealers do.

Federal law requires people who are in the business of dealing firearms to perform background checks through the National Instant Criminal Background Check System, run by the Federal Bureau of Investigation. Under the Firearm Owners Protection Act of 1986, though, people who make occasional sales and aren’t in the business of dealing firearms are not required to complete background checks on customers.

Federal legislation has been proposed that would require background checks for private dealers, but the bills have not been acted on. Gallup polls show the percentage of U.S. residents who support making gun control laws more strict decreased from 78 percent in 1990 to 44 percent in 2010. Congress has not approved any major new gun laws since 1994.

In response, some states have set their own laws to regulate private firearm sales. We would argue, though, that a federal approach would be most effective. Otherwise people could travel to a neighboring state that doesn’t require a background check in order to buy a gun and then bring it back to their home state.

The FBI reports that more than 100 million background checks were conducted in the last decade, leading to more than 700,000 denials — for reasons including that the person had been convicted of a crime punishable by more than a year in jail, had been committed to a mental institution or was subject to a court order restraining the person from harassing, stalking or threatening an intimate partner or child. Clearly some people — though a small minority — are trying to obtain weapons when they are prohibited from doing so.

No one benefits when guns are abused or used in crimes, including gun owners. Requiring private dealers to complete background checks on their customers is a reasonable way to make sure the law — that certain people not possess firearms — is actually followed. The tradition of gun ownership in the U.S. does not stand to suffer; the country has the most weapons per person out of any country in the world, with 90 guns for every 100 people.

Let hunters hunt, and let target shooters practice. By all means, people should own guns if it makes them safer or feel safer. But let’s not make it any easier for people who are legally barred from owning a gun to buy one.