There exists a long line of libel and slander rulings in California holding a plaintiff may not fabricate a cause of action by herself or himself publishing defamatory statements to others. The defendant must typically cause the publication. A plaintiff’s manufacturing a libel claim, for instance, does not create a valid legal cause of action.
However, courts have created an interesting exception to this rule. The deviation rests on the foreseeability that the defendant’s actions would cause required disclosure to a third person. This “necessity” exception arises in two settings.
The first context is where the original defamer believes (or has reason to) the disparaging comments will fall into the hands of a third party before the defamed party sees them or learns of their contents. This might occur, for example, where an unhappy employer notifies a journal or news outlet of what turns out to be the employer’s false, unprivileged, defamatory views of the employee.
The second “necessity” deviation from the general rule applies when there is a threat equal to coercion by the original creator of the defamatory statements. If the author of those statements has reason to believe the defamed person will face a compelled need to disclose them to a third person after that person has read or learned of its contents, there exists a necessity. This typically occurs when a plaintiff is compelled to republish the statements — often to disprove them.
For example, consider a terminated police officer. Where the instigator of defamatory allegations has reason to know the officer, discharged for the false accusations, must, when seeking employment with another police department, disclose to the prospective employer what the previous one alleged were the reasons (however false and defamatory) for the officer’s loss of her or his prior job, the necessity exception comes into play.
As Witkin explains, “the rationale for making the originator of a defamatory statement liable for its foreseeable republication is the strong causal link between the actions of the originator and the damage caused by the republication. The test to determine if the “coercion” exception is applicable is whether, because of some necessity he was under to communicate the matter to others, it was reasonably to be anticipated that the person defamed would do so.”
 Foreseeable Republication by Person Defamed., 5 Witkin, Summary 11th Torts § 634 (2018)