Sen. Angus King, I-Maine, speaks during a Senate Armed Services Committee hearing on the conclusion of military operations in Afghanistan and plans for future counterterrorism operations, Tuesday, Sept. 28, 2021, on Capitol Hill in Washington. Credit: Patrick Semansky / AP

A version of this article was originally published in The Daily Brief, our Maine politics newsletter. Sign up here for daily news and insight from politics editor Michael Shepherd.

Before announcing his 1994 gubernatorial run, Angus King left the Democratic Party. Shortly after that, he called it “too much the party that is looking for something from government” and went on to become Maine’s second unenrolled governor in the modern era.

But after being elected to the Senate in 2012 and reelected six years later, he has mostly been a reliable member of the Democratic caucus while retaining that independent branding. Last week, the group of Senate independents grew when Sen. Kyrsten Sinema left the Democratic Party as well. Her message was less about the party itself than partisan politics at large.

“In catering to the fringes, neither party has demonstrated much tolerance for diversity of thought,” she wrote in a column for the Arizona Republic. “Bipartisan compromise is seen as a rarely acceptable last resort, rather than the best way to achieve lasting progress.”

There have been many takes published on the Sinema situation. She was censured by her state party early this year for blocking a voting-rights bill by refusing to end the filibuster and has sat alongside Sen. Joe Manchin of West Virginia in the middle of the chamber given Democrats’ 50-50 Senate control that will bump up to 51-49 after a disappointing election for Republicans.

Sinema is a very different political figure than King, who has rejected ending the filibuster in the past but said he prioritized the voting-rights bill over that rule. She is in a different place in her career than the Maine senator was when he left his party, although both moves could be driven by electoral politics. Independence also has little effect on how the Senate actually works.

In 1994, King became an independent in large part due to former two-term Gov. Joseph Brennan going for the Blaine House again. Since he had the nomination locked down, there was little room for a challenger. On the other side, Republicans were preparing for a bloody primary in which Susan Collins emerged among eight candidates with just over 21 percent of votes. In the general election, Collins lost many conservatives with moderate social positions and then some moderates as her campaign faltered, which helped King win his first of two terms.

Sinema has not said whether she is running for reelection in 2024. But she already had a potential primary challenger in Rep. Ruben Gallego in a swing state where divisive Republican candidates have been on a losing streak to Democrats. Like King, Sinema could see bypassing that primary and rallying a smaller group of centrists to reelection in a fractured three-way race.

In an interview with CNN on Monday, the Maine senator bemoaned the effect of primaries when asked about Sinema, saying members increasingly risk getting picked off in primaries by working in good faith across the aisle.

“One of the problems with primaries today is that they tend to favor the activists on either side, Republican or Democrat,” he said.

Sinema is keeping her committee seats under an agreement with Senate Majority Leader Chuck Schumer, D-New York, and will not caucus with Republicans. In Congress, much of members’ individual power comes through those assignments, though Sinema has carved out an outsized role with her centrist positioning. That is one way to gain influence, and it is familiar to King. When he was governor, he could play the parties against each other on economic or social issues and make decisions hewing to his politics.

In the Senate, the work is ruled by up-or-down votes and getting state-specific items into bigger bills, plus doing constituent services. Compared to being governor, being one of 100 senators is necessarily a less-individual role. King has generally slotted into a second tier of more centrist senators within the Democratic caucus, behind Manchin and Sinema as a more loyal vote for leadership but not one that is fully guaranteed.

All of this means that Sinema’s decision, as pundit Matthew Yglesias has argued, should have a lot more of an effect on Arizona politics than national politics. Maine has seen this difference between branding and political effects since King jumped back into politics. Arizona may not see major fallout from Sinema’s move until the next election.

Michael Shepherd

Michael Shepherd joined the Bangor Daily News in 2015 after three years as a reporter at the Kennebec Journal. A Hallowell native who now lives in Augusta, he graduated from the University of Maine in...