Nothing federal prosecutors do is more important than protecting our fellow Americans from violence.

In recent years, however, we have lost one of the most important tools we use to protect our communities: the Armed Career Criminal Act.

Only Congress can restore the ACCA to help us keep our neighborhoods safe.

The ACCA operated on a simple premise: when a felon is convicted of illegally possessing a firearm, he receives a mandatory 15-year sentence if his prior convictions include three or more "violent felonies" or "serious drug offenses."

These "armed career criminals" are not low-level offenders but rather criminals who have already been convicted of multiple serious offenses and then were caught with a firearm.

In contrast to those included under the ACCA, lower sentences are given to felons who illegally possess firearms but lack that violent history.

Common sense tells us that when a felon with a violent past illegally possesses a firearm, he is extremely dangerous and must be incarcerated.

The ACCA was intended to bring that common-sense idea to the law.

For a long time, the ACCA really worked. After a period of increasing violent crime in America, President Reagan signed the ACCA into law in 1984.

From 1964 to 1980, the overall violent crime rate tripled in the United States. Robbery crimes and rapes tripled, and murders doubled.

Then came the ACCA and other major criminal reforms; the elimination of parole, reform of the bail system, the sentencing guidelines, and better funding for law enforcement.

The goal of these reforms was to reduce violent crime, and from 1991 to 2014, violent crime dropped by half.

Murders and aggravated assaults dropped by half, while robberies dropped by nearly two-thirds. The ACCA, along with these other reforms, was a resounding success that made our neighborhoods safer.

So what happened to the ACCA?

The answer is a 2015 Supreme Court decision called Johnson v. United States.

There, the Supreme Court considered whether Samuel Johnson, a white supremacist who admitted to planning acts of domestic terrorism, was properly deemed an armed career criminal after he was found guilty of illegally possessing an AK-47, several other firearms, and 1,000 rounds of ammunition.

The Supreme Court concluded that Johnson was not an armed career criminal because his prior conviction for illegally possessing a sawed-off shotgun was not a "violent felony."

Most importantly, in reaching that conclusion the Supreme Court held that part of the definition of "violent felony" in the ACCA was too vague to understand and thus violated the Constitution's guarantee of due process.

As a result, the Court struck that part of the definition from the statute, and now, after Johnson, many of the crimes that once were considered "violent felonies" under the ACCA no longer qualify.

It is no exaggeration to say that Johnson destroyed the common sense nature of the ACCA. Courts across the country have ruled that many plainly violent crimes are no longer "violent felonies."

Even murder is being challenged in some jurisdictions.

Here in North Carolina, our common law robbery crime — taking property from someone by means of violence or fear — is no longer a "violent felony," nor (believe it or not) is shooting into an occupied building.

It just doesn't make any sense, and clearly no one intended the ACCA to lead to these absurd results.

Because of Johnson, more than 1,400 violent career criminals have been released early, and 600 of those have already been arrested again just three years later.

On average, these 600 offenders have been arrested or reoffended three times.

As the Attorney General recently stated, "Releasing repeat offenders has consequences." Those awful consequences have been felt in our communities, such as in Utah, where a career criminal released because of Johnson tortured and murdered two teenagers, and in California, where a career criminal released after Johnson allegedly murdered his father, carjacked a vehicle, and killed the vehicle's driver.

Just last month in the Eastern District of North Carolina, Charlie O'Bryant Terry was sentenced to 20 years in federal prison for obstruction of justice and illegal possession of a firearm.

This was not Terry's first federal sentence.

In fact, in 2008, Terry had been sentenced under the ACCA to 15 years in federal prison after pleading guilty to being a felon in possession of a firearm after three prior violent felonies, including two common law robberies.

Because of Johnson, in August 2016, Terry's 15-year sentence under the ACCA was vacated when his previous convictions for common law robbery no longer qualified as violent felonies. As a result, Terry was released early and placed on federal supervised release.

In January 2017, a mere five months after his release from custody, Terry struck again, assaulting and robbing a couple at gunpoint.

During the assault, Terry placed a pistol in the mouth of one of the victims, and he cut the other victim's head by repeatedly hitting the victim with the firearm, requiring staples to close the wound.

After Terry was arrested in April 2017 for violating his federal supervision, federal agents executed a search warrant for Terry's cellular telephone and found that Terry had taken several "selfies," or photographs of himself, with an AR-15 semiautomatic firearm the day prior to his arrest.

While in jail, Terry also threatened one of the victims in an effort to change his testimony.

Terry received a 20-year sentence for his postrelease conduct, but if his sentence under the ACCA had not been cut short due to Johnson, Terry's victims would have been safe from his violent criminal behavior in the first place.

Johnson caused these violent offenders to be released early, and going forward federal prosecutors will no longer be able to ensure sufficient sentences for many repeat violent offenders caught illegally possessing firearms.

Innocent people will face the tragic consequences that will follow these offenders back to our streets, and the law enforcement officers who protect us will face the danger of confronting and arresting again the same violent felons they already removed from our streets years ago.

But amidst all this bad news, there is still room for something positive: Congress can fix the ACCA.

The Supreme Court in Johnson found part of the ACCA's definition unconstitutionally vague, but the Court left it open to Congress to craft a new definition that avoids these problems.

The Attorney General and the Department of Justice have been working with members of Congress to create awareness about this urgent problem.

The ACCA focuses on the most dangerous career felons — the kind we can and must take off the streets to protect our communities.

Congress made our nation so much safer in 1984 by passing the Armed Career Criminal Act. Now we need Congress to keep us safe in 2018 by fixing it — Higdon is the United States Attorney for the Eastern District of North Carolina