President Trump's racist tweets had an unintended consequence: They gave House Democrats a new rationale for impeachment.

Why it matters: This has the potential to fundamentally change the conversation around impeachment, which has so far mostly focused on possible instances of obstruction of justice as laid out by Robert Mueller's findings.

Driving the news: Democratic Rep. Al Green announced Monday at a Texas press conference that he would introduce articles of impeachment because of Trump's bigotry. He filed the articles Tuesday, in a move that will force a House floor vote by the end of this week.

"This is not about the Mueller report," he said. "This is not about obstruction. We can impeach this president for his bigotry in policy that is harming our society."

"This is about the president's statement that they should go back ... that statement in and of itself is a racist, bigoted statement," he added.

Our thought bubble: Does racism fit the definition of high crimes? Congress gets to define the term. And if past is prologue, one of Andrew Johnson's articles of impeachment was a non-criminal high misdemeanor of speaking ill of Congress.

By the numbers: A Pew Research poll from April found that 56% of Americans polled believe Trump has made race relations in the U.S. worse.

Almost two-thirds said "it’s become more common for people to express racist views since Trump became president."

Of course, this won't be easy for Green, even when Congress is still dealing with the aftermath of the president's comments about Reps. Alexandria Ocasio-Cortez, Ilhan Omar, Ayanna Pressley and Rashida Tlaib.

Speaker Nancy Pelosi has been working hard to keep her caucus as far away from impeachment as possible.

She's said it's politically divisive, not the right time, and that voters should decide in the 2020 election.

But after a week in which the same women who were targeted by Trump essentially accused Pelosi of being racist, will she latch on to the "Trump is racist" impeachment rationale instead?

Flashback: Green formally sounded the impeachment alarm on Dec. 5, 2017 when he sent a letter to his colleagues informing them he would introduce impeachment articles the next day.

In that initial letter, he talked about the president's bigotry. "He has incited hatred and hostility among the American people based on race, national origin, religion, gender, and sexual orientation," he wrote.

What to watch: It's too early to tell whether other members of the Democratic caucus, including Green's colleagues in the Congressional Black Caucus, will take up impeachment with him now that he's renewing bigotry as the reason.

Go deeper: A tough time to be a Trump supporter

Editor's note: This article has been updated to include Green's filing of the articles of impeachment.