Trump eventually responded on Twitter and elsewhere, reportedly calling her "the Indian."
On Tuesday, Trump went onto Bill O'Reilly to discuss the pair's tussle, saying Warren is "a Senator that (sic) has done nothing. She just talks."
Let that sink in.
He then doubled down on the Native American thing, again on Twitter, Wednesday:
Warren was ready. This afternoon, she came back in a new tweetstorm, calling his rhetoric "ugly" and "dangerous" while pointing out five ways Trump has contradicted himself on the campaign trail.
These tweets came on top of ones she issued last week warning the country about Trump's rise:
Warren has not yet endorsed either Democratic candidate running for president. But we know who she's not voting for.
Rob covers business, economics and the environment for Fusion. He previously worked at Business Insider. He grew up in Chicago.