President Trump referred to Mitt Romney as a "pompous ass" on Saturday in response to the Republican senator's criticism of Trump for his "brazen and unprecedented appeal to China and to Ukraine" to investigate the Bidens.
Why it matters: Romney, who criticized the Trump-Ukraine allegations after reading the whistleblower complaint, is one of the first Republican senators to denounce Trump's calls for China or Ukraine to investigate one of his top 2020 rivals.