A Down East physician who is “tired of seeing what’s going on” in Washington is likely to declare within weeks that she will challenge U.S. Sen. Susan Collins’ re-election in 2020.

“I can’t sit idly by and just watch this,” Cathleen London, who practices in Milbridge, said Friday. “I can’t keep watching this train wreck.”

London said she used to respect Collins for her independence and willingness to split with the Republican orthodoxy on issues such as abortion. But not anymore.

After the senator’s vote to block repeal of the Affordable Care Act last summer, London said, Collins has repeatedly sided with the GOP and President Donald Trump, instead of her constituents in Maine.

“Ever since, she’s gone the other way,” said London, a Democrat who serves on her party’s state committee.

She said Collins “sold us out on taxes” and has failed to stand up for Maine on a range of issues.

Collins is Maine’s senior senator, serving since 1997. Widely recognized as one of the few senators who is willing to cross party lines regularly, she has won re-election easily every six years.

But Collins may face a tougher time if she opts to run again in 2020. Max Linn, who made a fortune in finance, already has signs across the state bragging about how he is #TrumpStrong. He has said he plans to challenge Collins in a primary.

London said she is “very serious” about taking on Collins and will likely decide in the next couple of weeks after meeting with possible allies in the endeavor. But she talked as if she were already running.

London said at one point, “Now I’m going to come after” Collins because she won’t defend a woman’s right to autonomy over her own body.

When she hears men in Washington talking about abortion, London said, she wants to tell them to “get out of my exam room,” where real-life necessities are discussed rather than abstractions that hurt women.

She said Collins used to have wide backing in Maine. But “I haven’t talked to anybody who respects her anymore,” London said.

London said that when she sees what Collins and U.S. Rep. Bruce Poliquin are doing, she asks herself, “Are you, like, kidding?”

She said her disappointment with Collins is huge, especially her unwillingness to insist a successor to Supreme Court Justice Anthony Kennedy protect abortion rights.

“If she’s not willing to stand up for women and her constituents, I’m over it,” London said.

She said she heard from two doctors she knows at each end of the country urging her to challenge Collins.

“Someone has to stand up,” she said. “That’s what democracy is.”

London, who has talked about health care policy on television often over the years, said she loves practicing medicine and feels an obligation to her patients.

But, she said, she can also serve the public by bringing her expertise to the Senate.

London moved to Maine several years ago to help provide care in an underserved area of rural Maine.

By then she had 21 years of experience in medicine, including a practice in Brookline, Mass., and a five-year teaching stint at NewYork-Presbyterian/Weill Cornell Medical Center in New York City.

She’s a Brown University graduate who earned her medical degree at Yale University.

London, who has two grown sons, said it never occurred to her to run for office until this year.

But her Republican family always had a political bent. Her take on the issues made for some interesting discussions in her teenage years, she said, with her father convinced she was “a bleeding-heart liberal.”

London said, though, that she’s actually pretty moderate — a fiscal conservative and social liberal, someone who could have been comfortable in the GOP in the past but no longer.

Collins could not be reached for comment.

scollins@sunjournal.com