Senate Democrats delivered an embarrassing setback to the president Tuesday afternoon by choosing not to back his trade agenda, which failed to reach the required 60-vote threshold by a vote of 52-45. Opposition to the so-called fast-track legislation has been led by Democrat Sen. Elizabeth Warren, leading to several rhetorical jabs between the two recently.

Ohio Sen. Sherrod Brown has suggested that the friction between the two isn’t based purely in political ideology, but includes the taint of sexism as well. Politico’s Seung Min Kim reports that Brown, when asked at a press conference how he thought the president had been disrespectful to Warren, replied, “I think referring to her as first name, when he might not have done that for a male senator, perhaps? I’ve said enough.”

It’s complicated: