WASHINGTON ― Democratic nominee Hillary Clinton made history as the first woman to participate in a presidential debate on Monday. But she also changed the game in another way by calling her opponent Donald Trump what he is: a racist.

“He has a long record of engaging in racist behavior,” Clinton said onstage, after denouncing Trump for his “whole racist birther lie.”

The word “racist” has never been used in a televised presidential debate, according to Nicole Hemmer, an assistant professor at the University of Virginia.

“The charge came during a surprisingly frank discussion of racism from Clinton. In past presidential debates, discussion of race in the United States has often been discussed in the distancing language of ‘race relations’ or ‘racial problems,’” Hemmer explained to Politico.

“With discussions of race absent in the last two debate cycles, the depth and nuance Clinton brought to the issue was striking,” she added. “When asked how she would heal the racial divide in America, Clinton spoke in terms of individual hearts and minds, which she then connected to the larger issue of systemic racism.”

Addressing institutional racism, bettering community relations with police and tackling other injustices have become major issues in this year’s presidential campaign, thanks to the Black Lives Matter movement. Many potential voters of all races want to know how candidates plan to address mass incarceration, implicit bias and the staggering rates at which black people are killed by police.

“Too many young African-Americans and Latino men ended up in jail for nonviolent offenses, and it’s just a fact that if you’re a young African-American man ― and you do the same thing as a young white man ― you are more likely to be arrested, charged, convicted and incarcerated,” Clinton said during the debate.

The former secretary of state not only slammed Trump for leading the racist birther movement against President Barack Obama for five years, but also condemned him for being sued by the Justice Department for housing discrimination against black renters.

It’s not hard to find examples of Trump’s racism. This is a man who receives critical acclaim from white supremacists like David Duke and who hired Stephen Bannon, the executive chairman of Breitbart News Network ― a home for white supremacists ― as chief executive of his campaign.

Trump also wants to ban Muslims from entering the U.S. and to build a border wall to keep out Mexican immigrants, whom he’s called “criminals” and “rapists.”