The California Department of Education has threatened to sue two prominent Stanford University education professors to prevent them from testifying in a lawsuit against the department — actions the American Civil Liberties Union of Southern California calls an attempt to muzzle them. The ACLU, in turn, is threatening a lawsuit of its own — against CDE for infringing their and other researchers’ First Amendment rights. Observers say the dispute has the potential to limit who conducts education research in California and what they are able to study because CDE controls the sharing of data that is not available to the public. Studies using a wide swath of data could lead to legislation, or it could also prompt advocacy organizations like Public Counsel and the ACLU to pursue remedies through the courts to fix flaws in state laws or address poor student performance or inequities in funding. ACLU argues that preventing researchers from sharing their expertise with the plaintiffs would be prior restraint and deny the public a full and fair presentation of the issues. For this and other reasons, David Plank, the retired executive of Policy Analysis for California Education or PACE, a collaborative research and policy organization based at Stanford and several other universities, said he “would never have signed a contract in which we agreed to protect the interests or reputation of the agency with which we would have signed.”  To do so, he said, would be “contrary to the fundamental norms of academic research.”