The Democratic Senate primary in Maine is shaping up to be among the most significant proxy battles over Israel in the upcoming midterm elections, pitting the state’s moderate two-term governor against a left-wing populist upstart who has vocally embraced an anti-Israel platform.

Gov. Janet Mills, who announced her campaign to unseat Sen. Susan Collins (R-ME) on Tuesday and is backed by Senate Democratic leadership, is set to face a well-funded challenge from Graham Platner, a veteran and oyster farmer who boasts high-profile support from Sen. Bernie Sanders (I-VT).

In contrast with Mills, who has criticized anti-Israel divestment efforts in her state and warned against a “deeply troubling” rise in antisemitic incidents after Hamas’ Oct. 7, 2023, attacks, Platner has promoted more hostile views on Israel and its alliance with the United States.

Since entering the race in August, Platner has accused Israel of genocide in Gaza and endorsed measures to block U.S. arms sales to Israel. His campaign did not respond to a request for comment regarding the recently brokered ceasefire and hostage-release deal between Israel and Hamas.

Platner has also been an outspoken critic of the pro-Israel advocacy group AIPAC, whose affiliated political arm is supporting Collins, one of the most vulnerable Republicans now seeking reelection — in a state President Donald Trump lost by seven points in 2024.

“We are focused on helping to re-elect Senator Collins, who has long been a leader and champion of strengthening the partnership between the U.S. and Israel,” Marshall Wittmann, a spokesperson for AIPAC, told Jewish Insider on Thursday.

Wittmann did not address whether AIPAC has plans to get involved in the primary. Collins, a five-term senator, has defended her relationship with AIPAC, which has faced growing criticism from Democratic candidates in recent months as intraparty tensions over Israel have intensified.

It remains to be seen if the Maine Senate race will draw outside spending from other pro-Israel groups including Democratic Majority for Israel, which has engaged in a number of recent primaries. The group did not respond to requests for comment from JI.

The primary also includes Jordan Wood, a former congressional aide whose campaign says that he has raised $3 million since April. Dan Kleban, a brewery owner in Maine, dropped out of the race on Tuesday and endorsed Mills, who was aggressively recruited by Senate Minority Leader Chuck Schumer (D-NY). 

Mills’ campaign said this week that she had raised $1 million in the 24 hours after she announced her bid. Platner’s team reported a $4 million haul since entering the race over the summer, with prominent contributors ranging from Ron Klain, a former chief of staff to President Joe Biden, to the billionaire donors Donald Sussman and Chris Hughes, according to campaign filings.

While Platner, 41, has drawn scrutiny over his views on Israel — which he has made a central component of his campaign messaging and national fundraising appeals — the political newcomer has more recently weathered controversy surrounding past comments in which he identified as a “communist,” called “all” police “bastards” and said rural Americans are racist and stupid, among other incendiary statements.

Platner has said that such views, unearthed in a CNN investigation published on Thursday, do not reflect his current thinking. Still, the deleted posts underscore how a previously untested candidate is likely to navigate additional vulnerabilities in a race that Democrats view as one of their top priorities as they seek to win back the Senate majority next year.

Following Mills’ launch this week, Larry Sabato’s Crystal Ball, a top elections forecaster, said that it had changed its ranking of the Maine Senate race from “leans Republican” to “toss-up” — a rating also echoed by The Cook Political Report.

Mills — who, at 77, would be the oldest freshman senator in history if elected — has won praise from Sen. Kirsten Gillibrand (D-NY), the chair of the Democratic Senatorial Campaign Committee. The two-term governor also formed a joint fundraising committee with the Senate Democrats’ campaign arm earlier this week, according to a new campaign disclosure.

Mills’ campaign team features veterans of her 2022 bid for governor, a person familiar with the matter told JI on Thursday, including Eric Adelstein of the communications consultancy AL Media and Jefrey Pollock of the polling firm Global Strategy Group — which has conducted a number of surveys on Israel and the Jewish vote. 

Chelsea Brossard, a Democratic strategist who recently advised Rep. Josh Gottheimer (D-NJ) in his bid for governor of New Jersey, is also joining Mills’ team as campaign manager, according to the source, who asked to remain anonymous to discuss undisclosed details.

Mills’ campaign did not respond to requests for comment from JI on Thursday. Pollock declined to comment.