Lake Effect's Joy Powers, speaking with Reggie Jackson, head griot of America's Black Holocaust Museum.

More than 2 million people are currently imprisoned in the U.S. Although the country has just 4% of the world's population, it accounts for a quarter of the world's prison population.

So, how did the country get to this place? People point to different pieces of legislation as the main cause for mass incarceration. But researcher Reggie Jackson says it's the result of a complex web of laws and policy decisions that created this issue.

"You can't fight a 'war on drugs' unless you build an army first. And we had to set up the mechanism to create all of the ways to fund police, court systems, prison buildings — all of those things took place over a pretty extended period of time," he explains.

"You can't fight a 'war on drugs' unless you build an army first. And we had to set up the mechanism to create all of the ways to fund police, court systems, prison buildings - all of those things took place over a pretty extended period of time."

Jackson has a presentation called The 2.2 Million: The History and Human Cost of Mass Incarceration. It's premiering at the Shorewood Village Center.

"We have to go back to the 1960s, to policies under President Kennedy, President Johnson, and also, President Nixon, that kind of put the building blocks in place," he says.

President John F. Kennedy created the Committee on Juvenile Delinquency and Youth Crime, which Jackson says led to children and teens having more formalized contact with police officers. That led to more juveniles entering the criminal justice system. Jackson adds, "Typically, people who have contact with the police early on in their lives, who are arrested early on — they're much more likely to end up in prison as adults."

In 1965, under President Lyndon B. Johnson, the Law Enforcement Assistance Act was passed. Jackson credits the Law Enforcement Assistance Act as the "most important legislation that led to mass incarceration."

He explains, "For the first time in American history, it allowed the federal government to be able to work in collaboration with local and state law enforcement ... So, it basically opened the door for the federal government to be able to give funds to states and local communities for law enforcement to pay for more police officers, to pay for hardware for these officers, to pay for prisons. That was really the turning point in how we did criminal justice."

In 1974, the Juvenile Justice and Delinquency Prevention Act was passed. It created a large database of these young people with criminal records and funneled more kids into the system. Jackson also credits the act with fostering higher black incarceration rates, by deliberately directing high-risk white children to programs unavailable to black children.

As the fight against juvenile delinquency was occurring, American presidents found new foes to concur as well.

"President Johnson started what he called a 'war on crime.' President Nixon continued that 'war on crime,' and then he started a 'war on drugs.' That was continued under presidents after that ... President Ronald Reagan really issued this very dramatic call for a 'war on drugs,'" says Jackson.

The war on drugs during the Reagan administration roughly translated to a war on crack cocaine, which led to the first federal mandatory sentencing guidelines for drug possession. This, too, led to a racial disparity in who was using or handling these drugs, and who was incarcerated.

While many public officials have talked about the need for criminal justice reform, Jackson says that will be incredibly difficult because of how it's currently set up.

"We don't have a criminal justice system in the United States. We literally have over 3,000 criminal justice systems, because every county or county equivalent has their own district attorney and their own system in those counties. Then, we have the federal system and then we have the military system, as well," he explains.

"So we have all of these different systems that don't always work well together and reform in one county doesn't apply to the next county," Jackson adds.