President Barack Obama was not the only president to speak at the NAACP's National Convention for the 106th anniversary of the civil rights organization. On Wednesday, former President Bill Clinton addressed the crowd in Philadelphia.

He spoke about everything from the removal of the Confederate flag in South Carolina, to voting rights, to the minimum wage, and made a surprising admission: he made a mistake in his criminal justice policies.

"The president spoke a long time yesterday and very well about criminal justice reform, and I appreciate what he has done," Clinton said in reference to President Obama's Tuesday speech, which addressed criminal justice reform. "But I want to say a few words about it, because I signed a bill that made the problem worse and I want to admit it."

In 1994, Clinton signed an omnibus crime bill into law: the Violent Crime Control and Law Enforcement Act. In his speech, Clinton explained why he signed the bill into law citing a decade of rising crime and gang warfare.

The law implemented harsher sentences, provided more money for more police officers, and expanded funds for building more prisons. In effect compounding America's current state of mass incarceration. (Positive parts of this law expanded training for police and lawyers on domestic violence investigations and established a National Domestic Violence Hotline.)

This law also included the federal version of the controversial "three-strikes" law, which enacted "[m]andatory life imprisonment without possibility of parole for federal offenders with three or more convictions for serious violent felonies or drug trafficking crimes."

Twenty-eight states also have "three-strikes" laws for habitual offenders on the state level. California's 1994 "three-strikes" mandates that "[i]f a person has two or more previous serious or violent felony convictions, the sentence for any new felony conviction (not just a serious or violent felony) is life imprisonment with the minimum term being 25 years," according to the Legislative Analyst's Offfice. The maximum sentence is life.

The fact that the third strike can be any felony, means that somebody could be doing something such as receiving stolen property, or blocking a door during a bar fight, and be locked up for a minimum of 25 years. The California Legislative Analyst's Office gives the following example:

"As a result of these provisions, the Three Strikes law significantly increases the length of time some repeat offenders spend in state prison. For example, consider a defendant who has prior convictions for assault on a police officer and burglary of a residence, both considered serious or violent crimes. Subsequently, he is convicted for receiving stolen property, a nonserious and nonviolent felony. Before the enactment of Three Strikes, he would typically have served two years for the property offense. Under the Three Strikes law, he would be sentenced to life in prison. Figure 2 illustrates how sentencing under the Three Strikes law differs from the prior law under different scenarios of current and prior offenses."

"Three-strikes" laws—both federal and state—are part of the reason that there are currently so many Americans in prison. (And In 2012 California actually reformed their "three-strikes" practices, and according to the New York Times, roughly 2,300 prisoners who were in for life sentences have been released on time served.)

"Most of these people are in prison under state law, but the federal law set a trend," Clinton admitted in his Wednesday speech. “And that was overdone. We were wrong about that. That percentage of it, we were wrong about.”

"So the good news is we had the biggest drop in crime in history, and the first eight-year decline in history," Clinton continued. "The bad news is, we had a lot of people who were [unable to decipher] locked up, who were minor actors for way too long."

Many criminal justice policies implemented during this era—and through this 1994 bill—are now widely criticized. Nick Turner of the Vera Instituted told NPR the following in 2014:

"If you're a black baby born today, you have a 1 in 3 chance of spending some time in prison or jail. If you're Latino, it's a 1 in 6 chance. And if you're white, it's 1 in 17. And so coming to terms with these disparities and reversing them, I would argue, is not only a matter of fairness and justice but it's, I would argue, a matter of national security."