It is "completely inappropriate" for a president to encourage a foreign state to investigate a political rival, Republican Sen. Susan Collins of Maine said Saturday.
Addressing reporters after a memorial service for firefighters, Collins was asked what she thought about Republican President Donald Trump asking China to investigate Democratic presidential candidate Joe Biden and his son, Hunter Biden.
"I thought the president made a big mistake by asking China to get involved in investigating a political opponent," she said. "It's completely inappropriate."
Two other Republican senators, Mitt Romney of Utah and Ben Sasse of Nevada, have criticized the president's comments about China, which further fueled an impeachment inquiry in the U.S. House.
Collins reiterated that she would not comment on evidence that could be used in an impeachment proceeding, since she could serve as a juror in the Senate.
She said she hopes the process is "done with the seriousness that any impeachment proceeding deserves."