What was expected to be a free-for-all contest among Maine Democrats instead turned into a coronation this weekend. After Graham Platner ended his campaign to take on Senator Susan Collins in November, Maine's Democratic Party only had a couple of weeks to name a replacement to appear on the ballot instead of Platner. They could have used any method they wanted to select a new nominee, and the method they settled on led to an anticipation of a messy convention fight. Instead, what happened was one candidate essentially swept the field of challengers and will now (barring any unforeseen problems) be officially named the new Democratic Senate candidate at the party convention next weekend.

The process was designed to at least incorporate some sort of input from Maine Democratic voters, but without full participation by all of them. The result, however, was closer to what happened after President Joe Biden withdrew his candidacy for re-election and Kamala Harris wrapped up the party's nomination within mere hours. Whether what happened in Maine was the best way forward will doubtlessly be debated in the future, and it will depend in large part on whether Susan Collins is actually defeated in November.

The Democrat who will now take her on is Troy Jackson, a former state senate leader who ran for governor earlier this year. The key to his stunning victory was his support from Maine's Unions, who were far more organized than the supporters of any of the other candidates in the foreshortened race.

The process Maine's Democratic Party settled on for this nomination had two stages. Over the past weekend, the first stage took place. Meetings were held of Democrats in every county in the state to select the delegates to go to a miniature state convention, which will take place next weekend. The 101 members of the state party committee will participate with the 500 delegates that were chosen this weekend. Theoretically, the delegates selected over the weekend are supposed to be "unpledged" -- not locked in for any particular candidate -- but in reality the delegates were always going to be selected for their support for one candidate over the others.

There was another method the state party could have used, which was to hold an open caucus. This would have allowed all Democratic voters in the state to participate, and would have been a much more freewheeling event. What happened instead is that Jackson effectively swept the field by getting so many of his delegates (roughly three-fourths of the total) named to the convention that none of the other candidates really had a chance. As mentioned, Union support was key to this victory (because Unions are very good at political organizing in general, even on short notice). All the other major candidates bowed to this reality, in an effort to boost party unity heading into the November race:

Such was the scale of Mr. [Troy] Jackson's victories at the Saturday meetings that before any Sunday sessions began, his chief progressive rival, Shenna Bellows, the Maine secretary of state, ended her campaign. By dinnertime, the top moderate in the race, Dr. Nirav Shah, the state's former public health director, also suspended his campaign and endorsed Mr. Jackson, as did Dan Kleban, a local beer magnate, and Jordan Wood, a former congressional aide.

The question now -- which won't be answered until November -- is whether Jackson truly was the strongest candidate in the field to take on Susan Collins in the general election. In the Democratic primary for governor, Jackson only came in third, behind the eventual winner as well as Nirav Shah. Jackson's biggest drawback (which is already worrying some Maine Democrats) is that he isn't all that charismatic or a particularly good political speaker. He's going to have to work hard to replace Platner, who was both of those things (in a big way).

But Jackson certainly wasn't the worst choice Maine's Democrats could have made. In his run for the governor's office, he campaigned alongside Platner and won Platner's endorsement as well as the endorsement of Bernie Sanders. His policy positions are very close to Platner's as well -- Jackson supports Medicare-for-all, expanded child care, abolishing ICE, and other progressive positions. He has already been endorsed by Representative Ro Khanna and the political group founded by Bernie Sanders. He began his political career as a Republican, but shifted to the Democratic Party over 20 years ago and eventually disavowed his previous positions (on abortion and gay rights, most notably). Jackson has been described as the closest fit politically to the campaign Platner had been running. So it's not like the Maine Democratic Party replaced Platner with a middle-of-the-road establishment-backed candidate. Jackson is a progressive and a populist, just like Platner.

Jackson's biggest strength is that he is far more authentic a "man of the people" than even Platner. Platner ran on being a blue-collar worker and an oysterman, but he had a rather privileged upbringing that contradicted such an image. Jackson, however, is a "fifth-generation logger from Maine's northern reaches." He was born in a small town on the border with Canada and followed in the family tradition of becoming a logger. This could help him win over the voters who were supporting Platner for his championing of blue-collar workers. He has a pronounced northern Maine accent and wears baseball caps and T-shirts while campaigning.

His sweep of the process for naming convention delegates this weekend may have left some disappointment among the voters supporting the other prominent candidates, but the candidates themselves seem to be making a big effort to promote party unity:

"This has been an unprecedented nominating process, compressed into days instead of months, and I'm grateful to every volunteer who worked around the clock for this movement," Ms. [Shenna] Bellows said. "That energy is exactly what we need to beat Susan Collins in November -- and Democrats don't have a day to waste in unifying around that shared goal."

Dr. [Nirav] Shah pleaded with Democrats to unite behind Mr. Jackson.

"Susan Collins will not be defeated without a united Democratic Party," he said. "We cannot unite without treating one another with respect. No matter whom you supported in this race, I urge us all to remember that in the weeks ahead."

How this is all going to play out with the voters is the big unknown at this point. Will Democrats unite, as the other candidates are urging them to do? Will they fall in line behind Jackson? The biggest question is whether Jackson can maintain the enthusiasm that Platner's campaign had created, and how good a candidate he will actually be when facing Collins. As mentioned, the outcome of this race is going to be the deciding factor in whether the process used to replace Platner is seen in the future as the right way for the party to have gone or not. If Jackson successfully dethrones Collins in November then nobody's going to be quibbling about how things all played out in the selection process. However, if Jackson falls short then he (and the state party) are going to face the same sort of recriminations that Kamala Harris and the national Democratic Party faced after her loss.

For better or worse, though, the Democrats have now essentially crowned their new Senate nominee. Troy Jackson's victory in the delegate selection process was pretty impressive, with so many other possible Democratic choices in the field. But Susan Collins is going to be tough to beat, so we'll all have to wait and see whether this was the best choice for Maine Democrats or not.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant