Maine’s senior U.S. senator, Republican Susan Collins, issued a statement early Wednesday declaring her intention to seek a fifth term.

Though Collins has been running for months, raising more than $8 million and airing television commercials, she said she would make it official, or not, this fall.

U.S. Sen. Susan Collins, R-Maine, hands out candy to trick-or-treaters outside her Lewiston office during an event hosted by the local chamber of commerce. Oct. 25. AP photo

Now she has.

Collins, the fifth longest-serving senator in Maine’s history, said the fundamental question she asked herself in making her decision was: “In today’s polarized political environment, is there still a role for a centrist who believes in getting things done through compromise, collegiality, and bipartisanship?”

“I have concluded that the answer to this question is ‘yes,’ and I will, therefore, seek the honor of continuing to serve,” she said.

Collins, 67, has a few challengers already, including Democratic state House Speaker Sara Gideon of Freeport.

Political experts say Collins will likely face a fierce campaign as Democrats try to oust her from a seat in a state that leans slightly toward the Democrats.

Democrats argue that Mainers no longer consider Collins a centrist or a moderate, particularly after her vote last year to help put Brett Kavanaugh on the U.S. Supreme Court despite allegations he committed sexual assault as a young man. They also sharply criticize her 2017 vote for a $1.5 trillion tax cut that largely benefited corporations and the wealthy.

“When Senator Collins took office 22 years ago, she might have been different from other people in Washington, but it doesn’t seem that way anymore,” Gideon said in a prepared statement issued Wednesday. “These days, Senator Collins seems more focused on serving the special interests that fund her campaigns than the Mainers who elected her.”

The state’s Democratic Party chairwoman, Kathleen Marra, said in a statement that “Mainers are excited to elect a new senator, and Maine Democrats have been organizing. With Collins’ support in Maine at an all-time low, we’ve seen volunteer engagement more than double in comparison to the previous off-year and know this excitement will continue to grow.”

Holding on to Maine would likely cement continued GOP control of the Senate, where Republicans have a 53-47 majority. If Collins chose to retire, keeping the seat would almost certainly have been a tougher battle for her party than it will be with her on the ballot. Even so, it’s expected to be one of the hottest and most costly in the country next year.

In 2014, the last time Collins faced an election, she easily defeated Democrat Shenna Bellows.

Collins took office initially after winning the race for an open seat in 1996, two years after she lost a gubernatorial bid to independent Angus King, the only time in her career that she’s come up short at the polls.

Collins, the only Republican member of Congress left in New England, said in a letter to supporters issued before dawn that despite the “difficult and contentious times,” she has faith in the country’s ability to weather its challenges.

“Seventy-five years ago this week, U.S. forces were engaged in one of the most consequential battles of World War II, the Battle of the Bulge,” she said, where “American soldiers – including my father – courageously fought back, ensuring victory for the Allies.”

“That generation found ways to solve the challenges of their era, and I believe that we can as well,” Collins said.

“My commitment to you remains strong, and I am as determined as ever to keep bringing people together, to speak out for the values that unite our great country, and to deliver results for Maine and America.”

Collins said that growing up in Aroostook County, “I learned to work hard and to serve others. My parents set the tone, with their commitment to our fifth generation family business and with their devotion to public service.

“My father served in the state Senate, as did his father and grandfather before him, and my mother was mayor of Caribou and chairman of the University of Maine System board of trustees.  Their commitment to public service helped inspire me to run for the United States Senate.

“As Maine’s senator, I have had a number of important legislative successes that have benefited our state and the nation,” she said, citing her success in working to repeal a big tax break for tobacco companies, overhaul the intelligence agencies and bring more than $560 million back to Maine to improve roads, bridges, airports and seaports.”

“One reason why I have been able to pass so many laws is because of the bipartisan, common-sense approach I learned growing up in Maine. For the past six years, I have been ranked the most bipartisan member of the Senate,” she said, citing legislative successes she achieved alongside such Democrats as Dick Durbin of Illinois, Joe Lieberman of Connecticut, Tina Smith of Minnesota and Doug Jones of Alabama.

“Another reason I have been effective is because of the Maine work ethic that I learned as a child,” she said. “In Maine, we show up for work every day.  I have never missed a roll call vote – yesterday I cast my 7,234th consecutive vote.”

Gideon, who has raised more money than her Democratic opponents for the June 2020 primary, faces Hallowell activist Betsy Sweet, Saco lawyer Bre Kidman and Ross LaJeunesse of Biddeford, a former Google executive. Also in the running are Lisa Savage of Solon, a teacher seeking to represent the Maine Green Independent Party, and independent Danielle VanHelsing of Sangerville.

Collins, a Bangor resident who is married to lobbyist Thomas Daffron, has no GOP opposition. Her only challenger dropped out.

If Collins wins re-election, and serves out her term, only one Mainer — William Frye of Lewiston — will have served longer in the Senate. He died in office in 1911 after serving 30 years, 4 months and 21 days.

Should Collins come up short in the 2020 election, she would wind up as the fourth longest-serving Maine senator, logging just a few days less than one of her idols, Margaret Chase Smith of Skowhegan, who lost her bid for a fifth term in 1972.