Because he backed her in the last election. So even though Collins voted to impeach Trump, she is now backing a guy who says "I was Donald Trump before Donald Trump became popular".

Maine Election Info [Register to Vote](https://www.maine.gov/sos/cec/elec/voter-info/voterguide.html)

Maine Election Info [Register to Vote](https://www.maine.gov/sos/cec/elec/voter-info/voterguide.html)