That's a police officer. This video comes from his body camera.

At first, it seems like Kaia doesn't know what's happening.

Earlier that day, Kaia had a tantrum. Three school employees said she had kicked them.

The school called the police, who arrested Kaia on charges of misdemeanor battery.

The police dropped the charges -- after Kaia's grandmother sent this video to the Orlando Sentinel.

Kaia's case isn't an isolated incident.

"A five-year-old girl being handcuffed by police in Florida."

"For a year, he could not sleep alone."

"He put handcuffs on me."

"Tossed to the ground by a school resource officer."

What you're seeing are the effects of a larger problem in American schools:

The US doesn't treat all students equally.

But if we wanted to, we could do something about that.

The next president could decide if that happens.

In 2016, researchers at Yale devised showed teachers this video clip

of four preschool students.

Their instructions: look for misbehavior, and click when you see it.

The study was kind of deceptive. None of the kids in the video actually misbehaved.

The researchers were using eye-tracking software; what they actually wanted to study

was who the teachers were watching.

Both Black and White teachers spent significantly more time

watching the Black boy in the video.

This study showed that even preschool teachers

can treat kids differently based on their race without even realizing it.

Look elsewhere in the US school system, and you see this show up in other ways.

Like at this middle school in Bryan, Texas.

They gave students “tickets” for offenses like disrupting class, or using profanity.

Black students were four times more likely than white students

to receive those tickets.

Nationwide, Black boys miss way more school due to suspensions than any other group.

And this can start a kind of chain reaction.

Missing weeks of school due to suspensions makes students much more likely to drop out.

Without a diploma, you're much less likely to earn a living wage,

and much more likely to be incarcerated.

All this missed school is helping to drive the highest poverty and incarceration rates

in the developed world.

So it's worth asking, how'd we get here?

In 1964, President Lyndon Johnson created a new federal office, accountable to the President:

The Office for Civil Rights.

Its first task was to desegregate public schools in the South.

But soon, they started noticing that some schools

were segregating their students, without actually calling it segregation.

A lot of the Black students would be labeled disabled,

and removed from the mainstream classrooms.

So they wound up segregated.

Daniel Losen studies school discipline.

For years, he's been sounding the alarm

about how much school Black students are missing due to suspensions.

The data he uses in his reports comes from the Office for Civil Rights.

In the 1970s, they started requiring schools to report

how many students they classified as disabled,

plus suspensions and expulsions, all broken down by race and gender.

Over the next few decades, those numbers went up,

as more punitive ideas about discipline took hold in American schools.

Well, in some schools.

"Gangs and drugs have taken over our streets and undermined our schools."

The idea that if you don't throw the book at kids when they're young,

for every little thing, that they're going to turn into criminals.

There was never any research to show that it actually worked.

You never see that in schools serving mostly white kids.

But in 2011, a new report out of Texas started to cast doubt on that approach.

The study looked at discipline records for almost a million students.

It tracked the same kids, from seventh grade all the way through high school.

The results were stunning:

Nearly 60 percent of students had been suspended or expelled at least once.

The study also showed that Black students facing school discipline for the first time

tended to get harsher punishments than white students.

And the more disciplinary violations a student received,

the more likely they were to drop out.

Clearly, Texas had a big problem.

The question now was if the problem was bigger than Texas.

To figure that out, the Obama administration turned to the data set

that the Office for Civil Rights had built.

That's how they learned that this was a nationwide problem.

"African American students are over three times more likely then their white peers

to be suspended or expelled, often for very similar offenses."

They also discovered that the vast majority of suspensions

were for behaviors like talking back, using profanity, or violating the dress code.

"Non-violent student behaviors, many of which once meant a phone call home."

The administration started investigating school districts

where the numbers were the most damning.

One of those districts was Bryan, Texas.

Home of the discipline tickets.

In 2013, a woman named Marjorie Holmon filed a complaint,

after her twelve-year-old son was suspended for defending himself from a bully,

and had to appear in adult criminal court.

The Office for Civil Rights opened an investigation in Bryan,

along with hundreds of other school districts.

If you can't justify what you're doing, and it's having a harmful impact

one group more than others, you have to replace it with something else.

But we don't actually know if those changes made a difference.

Because the most recent data on the Office for Civil Rights' website

is from the 2015-2016 school year.

The year after that, things started to change.

"The 51-50 vote to confirm Betsy DeVos..."

"The Vice President votes in the affirmative, and the nomination is confirmed."

In 2017, the office of President Trump's new Education Secretary, Betsy DeVos,

sent a memo to the staff at the Office for Civil Rights.

This one super-jargony line in the memo signaled a huge shift:

"OCR will only apply a 'systemic' or 'class-action' approach

where the individual complaint allegations themselves raise systemic or class-wide issues."

Translation: no more looking for patterns in the data.

If the office got a complaint like Marjorie Holmon's, they would look for one thing:

written or verbal proof that an individual teacher or administrator

had punished Marjorie's son more harshly because he was Black.

We're not going to question that, unless there's a smoking gun of intentional racism.

That's what happened in Bryan, Texas.

When Betsy DeVos took office, the investigation into Bryan's schools was close to wrapping up.

The final report concluded that Black students were “subject to disparate treatment

when compared to White students engaged in the same or similar conduct.”

They had dozens of recommendations for the district:

Revise their discipline code, hire mentors and social workers, extra training for teachers...

DeVos's team scrapped the report, and closed the investigation,

with no finding of wrongdoing, and no suggestions for improvement.

If you look closely at this clip, you can see Joe Biden,

standing right behind President Clinton as he signs the 1994 Crime Bill.

That bill ushered in new “tough-on-crime” policies that devastated Black communities.

As a Senator, Biden played a key role in getting the bill passed.

"We have predators on our streets.

They are beyond the pale, many of those people."

And since then, he's had to confront that history.

"I haven't always been right.

There's systematic racism that most of us whites don't like to acknowledge even exists.

It's been built into every aspect of our system."

This policy plan comes from the Biden campaign.

In the section titled “School Discipline,”

It says that Biden would reinstate Obama's discipline guidelines,

and would push for every state to submit a plan

for “reducing the use of policies and practices that push kids out of school."

Some people believe that all racism is explicit.

A nasty slur, a “whites only” sign, a burning cross.

It's unmistakable, and it's on purpose.

But there's another way of understanding racism:

That laws and policies can have racist outcomes, even if they don't mention race at all.

That you don't always need a smoking gun to do a whole lot of damage.