Many ambitious Republicans eager to position themselves as future leaders of the party have picked sides. Last week, Cruz endorsed Sethi, joining Sen. Rand Paul of Kentucky. Two other 2024 presidential prospects, Sen. Tom Cotton of Arkansas and former Ambassador to the United Nations Nikki Haley, have lined up behind Hagerty, with Cotton’s super PAC set to make its first 2020 expenditure to attack Sethi.

The brawl between the two candidates escalated when Sethi went after Hagerty over his support of Romney in 2008 and 2012, branding him as a “Mitt Romney Republican” — scarlet letters in Trump’s GOP.

Since then, the race has devolved into a gnarly thicket of misleading attacks: Sethi’s campaign is running an ad that claims Hagerty is endorsed by Mitt Romney, even though the Utah senator hasn’t endorsed and Hagerty has denounced him aggressively on the trail. Hagerty’s team has accused Sethi of donating money to a group supporting the rioters, a distortion of a $50 contribution in 2008 Sethi made to a Democratic congressional candidate in Virginia that was processed by ActBlue, a party-aligned payment platform that has been used recently by Black Lives Matter-linked groups and other protestors.