In the wake of the shooting, people across the political spectrum—from President Donald Trump and Florida Sen. Marco Rubio to Senate Democrats and the Moms Demand Action advocacy group—have called for the strengthening of background checks on individuals looking to purchase firearms. According to a Quinnipiac University National Poll conducted after the shooting, 97% of Americans—and all-time high for the poll—support universal background checks.

There is nothing wrong with trying to improve background checks, but the system itself remains fundamentally inadequate.

In this instance, Nikolas Cruz—who the Broward County Sheriff’s Office says confessed to the mass shooting at Marjory Stoneman Douglas High School—passed a background check when he purchased his weapon from a gun store. That check would have been a simple, two-minute process in which the dealer placed a call to the FBI, which would have looked at whether Cruz had criminal background or mental health issues on record. Since nothing showed up, the sale went through.

Cruz had a history of troubling behavior—including disputes with neighbors, picking fights with other kids, and animal abuse—that frequently led to the police being called. Yet none of this showed up on his criminal record; a rap sheet is only the tip of the iceberg in terms of the crimes an individual has been involved with.

The Parkland shooting incident shows that we can’t just put a Band-aid on a deeply broken process. Instead, we need to create a comprehensive gun licensing system that would actually be able to catch criminals before they commit a mass shooting.

In Florida, licenses are required of motor vehicle operators, barbers, mold remediation service providers, contractors in the construction industry, and many other professionals. If those operating cars and construction machinery need licenses, it stands to reason that those operating lethal weapons should be licensed as well.

With this in mind, I propose a federal licensing system that would help prevent future mass shootings. Here’s what it would include:

1. Law enforcement would conduct an in-person interview and criminal record check of the prospective buyer. There would be no exceptions to this step for people who buy guns privately.
2. Law enforcement would speak with the prospective buyer’s references, inquiring if the individual had a history of violent behavior or substance abuse, and if they were emotionally stable.
3. Law enforcement would notify current and former domestic partners of a license application in order to provide them an opportunity to disclose previous acts of violence, threats, and any other troubling behavior from the prospective buyer.
4. The prospective buyer would undergo gun safety and skills training administered by law enforcement.
5. If under 26 years old, the buyer would undergo a psychological evaluation probing their level of anxiety, depression, and tendency toward violence and self-injury, as well as history of substance abuse. If they were to pass this, they would obtain a certificate of mental aptitude.
6. The prospective buyer would need to wait 10 business days to receive the license following the application and to renew their gun license every five years.

The proposed licensing system could have prevented Cruz from obtaining his weapons at four different points of the process:

1. The in-person interview may have uncovered that the suspect “had a fascination with guns,” according to the aforementioned Washington Post report, thereby deterring him from seeking a license and eventually a firearm.
2. Reference checks with peers, family (in this case, surrogate family) members, and school personnel, and a review of social media postings, may have uncovered Cruz’s troubling past behavior.
3. The psychological evaluation done for the certificate of mental aptitude may have revealed the suspect’s disturbing attitudes or past behavior.
4. The training requirement would have provided an opportunity for instructors to spot some warning signs as to what the suspect hoped to do upon receiving his license. Both in the classroom and on the range, the suspect might have shown an alarming level of aggression or a lack of care or restraint in the handling of a firearm.

States already have varying levels of licensing requirements for individuals looking to purchase firearms. These systems have proven effective in preventing gun homicides and gun trafficking.

But clearly that hasn’t been enough. A national system is needed, as porous state borders mean that individuals denied a license in one state could still obtain firearms in nearby states with lower standards. In addition, individuals can seamlessly transport weapons across state lines without having to deal with border controls.

Regarding constitutional concerns over such a federal licensing system, the District of Columbia v. Heller Supreme Court ruling in 2008 makes clear that laws imposing conditions and qualifications on the sale of firearms do not violate the Second Amendment.

A national licensing system would create an effective standard in regulating firearms to replace the patchwork quilt of state legislation that currently exists. It would ensure that only responsible Americans could purchase guns and, hopefully, prevent inadequately vetted individuals from committing more tragic massacres.

Thomas Gabor is a criminologist and author of Confronting Gun Violence in America.