Sen. Susan Collins of Maine became the third Republican senator to officially break with the party’s leadership and publicly criticize President Donald Trump for his public call for China to investigate former Vice President Joe Biden and Biden’s son Hunter. “I thought the president made a big mistake by asking China to get involved in investigating a political opponent,” Collins told Bangor Daily News. “It’s completely inappropriate.”

Collins also refused to take a public position on impeachment, saying that she hoped the process “will be done with the seriousness that any impeachment proceeding deserves.” But she said it would be inappropriate to comment any further considering the role she may have to play in the future. “Should the articles of impeachment come to the Senate—and right now I’m going to guess that they will—I will be acting as a juror as I did in the Clinton impeachment trial,” Collins said.

With her statement, Collins joined fellow GOP senators Mitt Romney and Ben Sasse in criticizing the president for his comments to China. “Hold up: Americans don’t look to Chinese commies for the truth. If the Biden kid broke laws by selling his name to Beijing, that’s a matter for American courts, not communist tyrants running torture camps,” Sasse said in a statement to the Omaha World-Herald that did not name the president. Romney was even more direct, condemning the president’s “brazen and unprecedented appeal to China and to Ukraine,” noting in a tweet Friday that it’s “wrong and appalling” to call on foreign countries to investigate a political opponent. Trump fired back at Romney in a series of tweets Saturday, including one in which he called for the senator from Utah to be impeached.

I’m hearing that the Great People of Utah are considering their vote for their Pompous Senator, Mitt Romney, to be a big mistake. I agree! He is a fool who is playing right into the hands of the Do Nothing Democrats! #IMPEACHMITTROMNEY — Donald J. Trump (@realDonaldTrump) October 5, 2019