NEW YORK -- Donald Trump can’t be sued for defamation by a political strategist who said her reputation was trashed after then-candidate Trump called her a “dummy” on Twitter during last year’s presidential campaign, according to a judge’s decision made public Tuesday.

Manhattan state Supreme Court Judge Barbara Jaffe ruled that though Mr. Trump’s tweets about public relations strategist and Republican consultant Cheryl Jacobus were “rife with vague and simplistic insults,” they were expressions of opinion protected by the First Amendment.

“Thus, although the intemperate tweets are clearly intended to belittle and demean plaintiff,” they wouldn’t prevent her from working as a consultant and political commentator, Jaffe wrote in a 20-page decision signed Monday.

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Jacobus’ lawyer, Jay Butterman, vowed to appeal the decision, adding that the ruling had effectively given “now President-elect Donald Trump a free pass to trample on the free speech rights of any critic.”

Larry Rosen, Mr. Trump’s attorney, called Jaffe’s decision “well-reasoned.” A transition spokeswoman didn’t immediately respond to a request for comment.

The case has its roots in a February appearance Jacobus made on CNN, in which she said the Republican candidate’s presidential campaign had not been transparent about its financing.

Jacobus had previously had two meetings with then-Trump campaign manager Corey Lewandowski in the summer of 2015 about a possible job with the campaign. And though no job offer was ever made, both Mr. Trump and Lewandowski publicly attributed Jacobus’ criticisms to her lack of employment with the campaign.

Mr. Trump tweeted that Jacobus had “begged us for a job. We said no and she went hostile,” calling her “a real dummy.” Days later he tweeted that she was a “major loser, zero credibility!”

Jacobus filed a $4 million lawsuit, saying Mr. Trump’s online attacks had cost her TV appearances and inspired bullying Twitter behavior from Trump supporters.

In her decision, Jaffe ruled that whether Jacobus “begged” Mr. Trump for a job, as he had tweeted, was subjective, rather than an objective fact.

Because it followed her own public criticisms of Mr. Trump, Jaffe ruled, the context of the exchange “signals to readers that plaintiff and Mr. Trump were engaged in a petty quarrel.”