She [told CBS News] (https://www.cbsnews.com/news/susan-collins-explains-her-vote-to-acquit-trump/): “The president has been impeached. That’s a pretty big lesson. I’m voting to acquit. Because I do not believe that the behaviour alleged reaches the high bar in the constitution for overturning an election, and removing a duly elected president.”

https://www.independent.co.uk/news/world/americas/us-politics/susan-collins-trump-impeachment-vote-b1841021.html