The strange saga of a Park Slope principal accused of promoting communism took another turn Wednesday, when her request for a temporary halt to the probe against her was denied.

Jill Bloomberg, principal of Park Slope Collegiate, is known for her activism, particularly around the issue of school segregation. But the Department of Education says now she’s gone too far by sharing her political views at school and “actively recruiting” students into a communist organization.

“We lost the battle, not the war,” said Bloomberg’s attorney Jeanne Mirer after the judge’s decision to allow the investigation to proceed.

The war, it seems, will partly depend on whether Bloomberg violated D-130 — a Chancellor’s regulation that prohibits school employees from “being involved in any activities, including fundraising, on behalf of any candidate, candidates, slate of candidates or political organization/committee during working hours.”

The city claims, among other allegations, that Bloomberg violated the regulation by advocating on behalf of the Progressive Labor Party, a political organization with communist ties, at school. Bloomberg denies that and says she isn’t a member herself. But the case raises a larger question of what the regulation is meant to cover.

Mirer says a close read suggests it only bars election-related political activity — campaigning for a candidate, for instance — and not the type of organizing of which Bloomberg is accused.

If it did cover non-electoral politics, she said in court Wednesday, that would create a slippery slope for any educator who dared to voice a political view. “Any ideological belief could be the subject of a violation,” she warned.

Judge Paul Gardephe seemed unmoved by her argument. “I read the relevant parts [of D-130],” he said. “This lawsuit is not about whether D-130 is fair.”

But Mirer is not alone in worrying about how the regulation is being applied. Arthur Eisenberg, legal director at the New York Civil Liberties Union, is advising Mirer and has his own concerns about the free speech issues at play.

According to Eisenberg, the rules are the same for students, teachers and principals: “It’s well-established that school officials do not lose their First Amendment rights to speak out as citizens even when they are in school,” he said. “The standard is they can’t speak out in ways that are disruptive to the functioning of the school.”

Eisenberg declined to speculate on whether or not Bloomberg might have done that, but he said he was confident that D-130 could only apply to electoral politics.

A broader interpretation, he said, “puts the DOE in the position of having to regulate issue-oriented speech in ways that make it difficult to know how and where to draw the line.” Limiting free speech on issues that are political in nature, he said, could potentially impact student clubs that deal with gay rights, for instance, environmental causes, or racism. “And we know that can’t be right,” he said.

Eisenberg also questioned another line in the regulation quoted in the city’s court documents, which calls for a “posture of complete neutrality” on political candidates. Even if that were possible, he said, it wouldn’t be desirable.

“The obligation of an academic or teacher is to engage in critical judgment and to support those judgements with reasoning and fact,” Eisenberg said. “And that may be inconsistent with a principle of absolute neutrality.”

We asked the city’s law department what it made of Mirer’s argument that D-130 was meant to be more narrow in scope. Nick Paolucci, a spokesman for the department, said he wasn’t familiar with argument and couldn’t comment.