Maine Dem Gov Janet Mills leans into Trump rift in announcing bid to unseat GOP Sen Collins

Maine Democrat Gov. Janet Mills on Tuesday announced her expected bid to challenge incumbent GOP Sen. Susan Collins for her seat, mentioning President Trump by name and saying she's "never backed down from a bully."

Mills' campaign-launch video includes a clip of Trump confronting her in February at the White House for defying his executive order preventing trans athletes from competing in girls and women's sports.

Senate Minority Leader Chuck Schumer has urged Mills to join the race, with unseating Collins critical in Democrats' effort to regain the Senate majority, according to Fox News. Collins is the only Republican senator up for reelection next year in a state the Democrats carried in the presidential election, the news outlet also reports. 

However, the 77-year-old Mills faces a crowded and competitive primary. And if Mills unseats Collins, she would be the oldest freshman senator in U.S. history. 

"I've never backed down from a bully and I never will," Mills said in announcing her campaign. "Donald Trump is ripping away health care from millions, driving up costs, and giving corporate CEOs massive tax cuts. And Susan Collins is helping him."