Maine House Speaker Sara Gideon had led GOP Sen. Susan Collins in polls public and private, Republican and Democratic for months. Her likely victory over the longtime incumbent was a key building block in Democrats plan to retake the Senate after six years in the minority.

But in the final weeks of the 2020 election, Democrats started to worry. Their internal polls showed Collins not only fighting back, but closing the gap with Gideon. In the days leading up to the election, Senate Minority Leader Chuck Schumer (D-N.Y.) called other members, warning them Gideon may lose. Republicans saw a similar uptick, though many still thought Gideon would triumph after Maines ranked-choice voting process.

Instead, Collins romped, winning 51% of the vote to Gideons 42%. Even if the ranked-choice voting process had eliminated two independent candidates, Gideon likely only would have reached about 47%.

Republicans and Democrats working on Senate races quickly reached the same, somewhat unexpected conclusion. The death of Supreme Court Justice Ruth Bader Ginsburg which both sides thought would hurt Collins chances by reminding Maine voters of her unpopular decision to back Brett Kavanaughs Supreme Court confirmation in 2018 instead gave her a renewed chance to highlight her independence with her vote against the nomination of Justice Amy Coney Barrett, persuading enough swing voters to cast ballots for both her and Democratic presidential nominee Joe Biden.

Senate Democrats entered the fall riding high. While only two of the states they were targeting Colorado and Maine voted for Democratic presidential nominee Hillary Clinton four years earlier, they believed they had created a map of almost unprecedented breadth. With the help of millions of dollars of grassroots fundraising, Republican-leaning states from Alaska to Montana were in play, and swing states like North Carolina and Arizona seemed to be trending in the Democratic direction.

Super PACs allied with Senate Majority Leader Mitch McConnell (R-Ky.) agreed with their wallets, pouring tens of millions of dollars into defending incumbents like Lindsey Graham in South Carolina and Steve Daines in Montana.

Democrats still have a chance at winning the Senate, where before the election they had a 53-47 disadvantage. Theyve won two states Colorado and Arizona while suffering an expected loss in Alabama. But their once-optimistic chances have now faded dramatically, reliant on either a miracle win in Alaska or on sweeping two runoff elections scheduled for January in Georgia.