WASHINGTON — The president of the United States proved unable to make it a full 56 hours into Native American Heritage Month without insulting a U.S. senator for her claimed Native American heritage.

Reviving one of his favorite old jibes, President Donald Trump referred to Sen. Elizabeth Warren (D-Mass.) as “Pocahontas” in a Twitter post early Friday.

Pocahontas just stated that the Democrats, lead by the legendary Crooked Hillary Clinton, rigged the Primaries! Lets go FBI & Justice Dept. — Donald J. Trump (@realDonaldTrump) November 3, 2017

Although no surprise coming from Trump, this particular epithet came just three days after he declared November as Native American Heritage Month. In his proclamation, Trump said the month was a time to “honor and celebrate the first Americans and recognize their contributions and sacrifices.”

“Native Americans are a testament to the deep importance of culture and vibrancy of traditions, passed down throughout generations,” he said. “This month, I encourage all of our citizens to learn about the rich history and culture of the Native American people.”

Warren identifies as part Native American, although there is little evidence to back up the claim. For whatever reason, Trump remains fixated on the senator’s lineage, frequently referring to her as Pocahontas.

Last year, while on the campaign trail, Trump — who has a history of racist comments — went so far as call Warren the racist.

“Elizabeth Warren is a total fraud,” he told NBC’s Hailey Jackson in June 2016. “I know it. Other people who work with her know it. ... She made up her heritage, which I think is racist. I think she’s a racist, actually, because what she did was very racist.”

Warren responded to Trump’s name-calling Friday in her own Twitter posts.

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You might think your tweets are cute, @realDonaldTrump, but they won’t stop Mueller's investigation or keep your people out of jail. — Elizabeth Warren (@elizabethforma) November 3, 2017

Slurs, lies & trash talk won’t stop the FBI from doing its job. This isn't a dictatorship. It's our democracy. And it's stronger than you. — Elizabeth Warren (@elizabethforma) November 3, 2017

The clashes with Warren aren’t the only example of Trump displaying his insensitivity to people with Native American lineage.

During a congressional hearing in 1993, Trump accused competing Native American casinos of being fronts for the Mafia and being run by non-tribal members. “They don’t look like Indians to me,” he said. “And they don’t look like Indians to Indians.”

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This article originally appeared on HuffPost.