Former independent Maine governor Angus King will announce Monday night whether he will run for the state’s open Senate seat, potentially adding a major variable in the race to succeed retiring Sen. Olympia Snowe (R-Maine).

Multiple media reports, citing anonymous sources, have said King will indeed run for Snowe’s seat. King himself has not confirmed it, and his former campaign manager, Kay Rand, told The Fix: “This is his announcement to make, not mine.”

King, who served two terms in the governor’s mansion between 1995 and 2003, was extremely popular during his time in office. And in 1998, he was reelected with 59 percent of the vote despite facing both a Democrat and a Republican.

He also has personal wealth which he can use to fund a campaign — a hurdle most independent candidates face.

While King might be the early favorite for Snowe’s seat, his entry would also be a potential boon to Republicans, because the King could well take more Democratic votes than Republican ones.

King, who is socially liberal, served as an aide to Democratic former senator William Hathaway before opting to run for governor as an independent. He is generally considered to be more left-leaning.

King did endorse Republican George W. Bush for president in 2000 but then picked Democrats John Kerry and Barack Obama in 2004 and 2008, respectively.

Maine has a long history of independent politicians, and voters have shown a willingness to vote for them, so it’s hard to simply call King a spoiler. But he probably would increase the GOP’s chances of winning in a blue state — provided he himself doesn’t win the race.

Republican Paul LePage won the state’s governorship in 2010 in large part thanks to an independent candidate, Eliot Cutler, stealing Democratic votes and lowering the threshold for victory.

Cutler announced Monday on his Facebook page that he will not run but would encourage King to run. King endorsed Cutler in 2010.

“I have had several long conversations with Angus King during the past week, and I hope that he will run for the U.S. Senate,” Cutler wrote.

Rep. Chellie Pingree (D-Maine) appears to be the early Democratic front-runner, while Republican state Attorney General Bill Schneider announced this weekend that he will run.

Snowe announced last week that she will not run for reelection, opening up a previously safe Republican seat to a potential Democratic takeover.

If King were elected, the Senate would continue to have two independents. Sen. Joe Lieberman (I-Conn.) isn’t seeking reelection. Both Lieberman and Sen. Bernie Sanders (I-Vt.) are technically independent but caucus with Democrats.