(CNN) As House Democrats staged a sit-in in Congress in the wake of the shooting at a nightclub this month in Orlando, the public has again been left wondering if there is any politically feasible path to dealing with this country's problem with mass shootings.

Of course, America isn't the only country to have experienced mass shootings. Australia suffered a string of them before deciding to take action back in 1996, when it responded with a complete ban on the possession of rapid-fire rifles and overall tightening of its overall gun regulation regime. The results have been stunning: The country has not had a single mass public shooting in 20 years.

There is no chance of such dramatic action here. But when videos have surfaced urging extremists to take advantage of America's lax gun laws, then you know it's well past time to examine what steps can be taken to diminish the chances of more mayhem.

There are four steps the United States should be taking right now, ideas that no one -- aside from those trying to profit from gun sales -- should reasonably object to.

First, anyone who is on the " no-fly" list because of suspected terrorist leanings or activity should be a prohibited purchaser. Second, federal law must require background checks for all gun sales . These two proposals should not be treated as separate issues. After all, implementing the first proposal without the second would be like having a screening line at the airport but making it voluntary. Obviously, the terrorists would skip the line. Making terrorists prohibited purchasers while allowing them to buy guns through private sales would be similarly ineffectual.

Third, the background check system needs to be strengthened by making sure all prohibited purchasers are included in the system -- and that the FBI has time to evaluate whether a purchaser is indeed legitimate. At present, many states have failed to furnish the names of prohibited purchasers, and guns have been turned over to killers simply because the three-day mandated period for investigation was too short to ascertain the necessary facts.

nine church members a year ago in Charleston, South Carolina, will be kept from getting weapons. I am sure legitimate purchasers will not mind the minor inconvenience of an additional day or two waiting if it means that individuals such as Dylann Roof , accused of killingnine church members a year ago in Charleston, South Carolina,will be kept from getting weapons.

Fourth, the police, prosecutors and the public must take the initiative to see that all prohibited purchasers are properly added to the rolls. The Orlando shooter is alleged to have been a violent wife abuser. Victims and other observers must be encouraged to bring such misconduct to the attention of the authorities so they can add such individuals to the prohibited purchaser list.

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In addition to an improved and universal background check system, we must also look at a return to the federal assault weapons ban , with appropriate tightening of its many loopholes. This is more controversial, because while few other than gun sellers oppose attempts to keep guns away from prohibited purchasers, those who like to own assault weapons will oppose restrictions that keep them from buying the weapons they want.

Why would gun sellers object to tighter laws? The answer lies in the nature of the gun market. Despite a recent uptick captured in a 2012 survey , hunting has declined over the past three decades , which means that gun sellers need to find ways to get people who have already bought a gun for self-protection to buy more weapons. Since guns last for decades, there is no obvious need to buy more, so the industry tries to pump up sales by stressing the need to secure more powerful, faster-shooting weapons.

Modern assault weapons are as deadly as the machine guns used by Al Capone in the 1920s and '30s and should similarly be banned -- as should all weapons and high-capacity magazines that exceed a given threshold of deadliness because they allow for rapid fire of large numbers of particularly damaging bullets. Since the AR-15 was designed to be as lethal as possible, it clearly falls on the wrong side of the permissible line for civilian use.

National Rifle Association darling John Lott has stated that " 98 percent of the time that people use guns defensively, they merely have to brandish a weapon to break off an attack." By that reasoning, nothing more than a revolver is needed for self-defense in the overwhelming majority of cases. The idea that assault weapons are really "protection weapons" permitted by the Second Amendment is not credible.