Sen. Susan Collins, R-Maine, returns to the Senate chamber from the afternoon break in the impeachment trial of President Donald Trump on charges of abuse of power and obstruction of Congress, at the Capitol in Washington, Friday, Jan. 31, 2020. Credit: J. Scott Applewhite | AP

U.S. Sen. Susan Collins’ campaign said Friday it raised $2.3 million in the final quarter of 2019, bringing her total fundraising this cycle to $10.9 million as she heads into the most competitive reelection campaign of her career.

It was Collins’ strongest fundraising quarter yet but still the second straight one in which she was outraised by House Speaker Sara Gideon of Freeport, a Democrat who raised $3.5 million during the same period. Gideon is one of four Democrats running in June for the party’s nomination to face Collins, a Republican.

Collins has spent significantly less than the Freeport Democrat so far, however, and has $7.2 million in cash on hand, which is more than 2.5 times Gideon’s warchest of $2.8 million. Both campaigns released topline figures this week before a Friday due date for new filings with the Federal Election Commission.

The incumbent Republican has already set a record for the most raised by any campaign in Maine’s history. Her seat is one of a few that Democrats may be most likely to flip in 2020 and the race is expected to break spending records. Collins’ vote to confirm U.S. Supreme Court Justice Brett Kavanaugh in the fall of 2018 prompted liberals to raise millions for her eventual opponent. She has also received significant support from Republicans nationally.

Gideon is the establishment-backed candidate in a four-way race with former Google executive Ross LaJeunesse of Biddeford, progressive lobbyist and former gubernatorial candidate Betsy Sweet of Hallowell and lawyer Bre Kidman of Saco. Green candidate Lisa Savage and at least three independents are trying to get on the November ballot.