Rarely a day goes by on the campaign trail without someone accusing Donald Trump of being racist.

In a new tweet Saturday morning, he said he's not.

Mitt Romney had his chance to beat a failed president but he choked like a dog. Now he calls me racist-but I am least racist person there is — Donald J. Trump (@realDonaldTrump) June 11, 2016

In case you're just tuning in to what has become an election full of vitriol, here's what you need to know about the latest Trump tweet:

Just after Trump vowed to stop making comments about a federal judge's Mexican heritage, he started calling Sen. Elizabeth Warren "Pocahontas" again.

These recent remarks have left some Republican leaders struggling for words to describe their party's presumptive nominee, according to The Washington Post.

U.S. District Judge Gonzalo Curiel, who is overseeing a Trump University lawsuit, was born in Indiana, but his parents were born in Mexico.

Trump said that heritage creates a conflict of interest in the lawsuit because the presidential candidate wants to build a wall along the U.S.-Mexico border to stop illegal immigration.

That rationale is textbook racism, according to House Speaker Paul Ryan.

Former House Speaker Newt Gingrich, who is considered to be a favorite for Trump's running mate, also condemned Trump's words.

Similarly, a Republican senator struggled to answer questions from a reporter Friday after Trump called Warren "Pocahontas," referring to her claim of having Native American ancestors.

Trump also called her "goofy" in the speech - the latest in response to Warren's eviscerating comments this week when she called him a "loud, nasty, thin-skinned fraud."

He's also taking heat from Mitt Romney, who was the Republican Party's nominee in the 2012 election. Romney said Trump will change America with "trickle-down racism."

And that's what Trump responded to in his tweet Saturday morning.