Weingarten defended the project in a tense exchange with "The Story" host Martha MacCallum a day earlier, where she stated that "from everything that I can see and understand from the data that I see, 1619 was the year that the first slave boat came from Africa to the United States."

MACCALLUM SPARS WITH TEACHERS UNION PRESIDENT OVER CRITICAL RACE THEORY

The project is based on the belief that the first importation of the slaves to American shores in 1619 constituted the nation’s true founding, and suggests "that the reason for the founding of our country was to perpetuate slavery," DeVos said.

"Let's be really clear. The 1619 Project is not history... it denies 1776 and our constitution and our founding documents and the goal of forming a more perfect union," the Trump education secretary said.

"Let's be really clear. The 1619 Project is not history."

— Betsy DeVos, 'The Story'​​​​​

DeVos, who last year battled with Weingarten over school reopenings with repeated warnings surrounding the ramifications of long-term remote learning, accused the union head of "skirting the issue" by suggesting "that that those who don't believe that 1619 is an important year denies the reality of slavery. 

"Of course we need to teach history. We need to teach about slavery," she said, "but we also need to teach how our country has continued to aspire for and work toward a more perfect union. And the answer to racism and discrimination in our country is not to then adopt another form of racism, which is exactly what the 1619 Project suggests."

DeVos also dismissed Weingarten's attempt on Monday to assign blame on the Trump administration for politicizing school reopenings and intentionally delaying a full return.

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"It's an outright lie," DeVos fired back, noting the prior administration's aggressive efforts to reopen schools nationwide and the union's refusal until their demands for additional funding were met. 

"The blame lies right at the feet of the teachers union and all of their allies. We knew last spring that it was safe for kids to be back in school. They were going back to school around the world safely. And that's what we called for," she said. "That's what we encouraged that’s what we urged. Here we are nearly a year later and kids have fallen further and further behind as a result. It's a tragedy."

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DeVos accused the union of dragging its feet "simply because of politics."

"The union saw an opportunity to impact the election, they saw an opportunity to have a money grab even more than what they have already -- what they already got. And they played hardball in a way that is an absolute travesty for kids," she said.

"Here we are again a year later, kids that -- the ones that are most vulnerable are the ones that are most hurt. We won't know for years what the long-term impact of this has been."