Graham Platner’s ex-political director expressed her growing concern about the embattled Maine Democrat in a Washington Post op-ed Monday, arguing that her former boss “‘shouldn’t be a US senator.”

“I quit the campaign in October, disturbed by what I learned about the candidate and concerned about his potential impact on the Democratic Party’s prospects in my home state,” Genevieve McDonald wrote. “As Tuesday’s primary arrives, I want to make clear what transpired since August and why my concerns have only grown.” 

McDonald argued that Platner “exhibits a pattern of dishonest behavior that is impossible to ignore.”  

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“Despite being exposed by a series of scandals beginning last October, he kept assuring voters and the Democratic Party that there were no more skeletons in his closet,” she continued. “Then more emerged — the latest, in recent days, have involved former girlfriends’ serious accusations of physical mistreatment.” 

McDonald described herself as “one of the Platner campaign’s first gaslighting casualties,” claiming the candidate and his campaign dismissed her concerns about his Nazi tattoo and electability. 

“I was willing to believe his explanations, I wanted to believe, until his flaws as a candidate became impossible to ignore,” she wrote. 

McDonald said she “realized the campaign had not been honest” when reports on Platner’s disturbing Reddit post history started to surface. 

She claims the Platner campaign offered her “$15,000 to sign a nondisclosure agreement,” after her resignation, which she refused to do so, and that “over the past eight months, women have come to me with their own disturbing stories about Platner.”

“Enough is enough,” McDonald wrote.

McDonald was one of three officials who quit Platner’s campaign last fall after wild details about his past emerged.

She previously recounted how Platner’s wife, Amy Gertner, informed her that she discovered her husband had sent sexually explicit images to various women while the campaign was doing internal opposition research to prepare for potential dirt his rivals might be able to dig up.

Platner, a Marine veteran and former oyster farmer, has faced numerous controversies since launching his campaign, including the sexting scandal and Reddit posts he made downplaying sexual assault, mocking soldiers and contending that white Americans “actually are” racist and stupid, among others.

One of the Senate hopeful’s ex-girlfriends, Lyndsey Fifield, alleged in the New York Times last week that Platner was abusive – once twisting her arm during an argument and shoving her into a bedroom.

Fifield also claimed Platner would routinely grab her by the shoulders, sometimes hard enough to leave marks, and one time forced her out of a cab that she did not want to exit by yanking her wrist. 

Platner’s ex also remembered him boasting about having a Nazi tattoo and calling it “my Totenkopf” — which contradicts the Democratic candidate’s claim that he only realized last fall that he had the Nazi SS death squad symbol on his chest.   

The Maine Democratic Senate primary will be held Tuesday. 

The winner of the contest will take on incumbent Sen. Susan Collins (R-Maine) in November. 

“Democrats are being sold a narrative that Platner is the only choice for the race against Republican Sen. Susan Collins,” McDonald wrote. “Maine voters don’t have to accept that. 

“There are two other named candidates on Tuesday’s ballot.” 

McDonald urged Democrats to “demand better from those entrusted with power or seeking it.” 

Platner’s campaign did not immediately respond to The Post’s request for comment.