In contrast to the threatened violation of a non-competition agreement by a former employee, where New York's courts have expressed a willingness to issue an injunction, or temporary restraining order ("TRO") (see, e.g., "How Violation of a NY Non-Compete Can Be Deemed 'Irreparable Harm'"), the same cannot be said in the context of defamation (i.e., slander or libel) cases.
"Why not?" you ask.
Because unlike the context of the breach of fiduciary duties associated with the violation of a non-compete or non-solicitation agreement, generally speaking the victim of defamation can be made whole through monetary damages.
To that end, New York's courts have expressed the rule as follows:
"The fact that false statements may injure the plaintiff in his business or as to his property does not alone constitute a sufficient ground for issuance of an injunction." Bynog v. SL Green Realty Corp., 2005 WL 3497821, at *3 (S.D.N.Y. 2005) (citing inter alia, Donini Int'l, S.P.A. v. Satec (U.S.A.) LLC, 2004 WL 1574645, at *7 (S.D.N.Y. 2004) ("[T]he long-standing rule in this Circuit is that equity will not enjoin threatened libel or defamation since there are adequate legal remedies available for damages arising from harmful speech")).
While damages for these loss are difficult to compute, there must be some evidence that they are likely to occur. Astronics Corp. v. Patecell, 1986 WL 11889, at *3 (W.D.N.Y. 1986). Where plaintiffs have an adequate remedy at law, injunctive relief is unnecessary. See id.; see also Ameritech v. Voices For Choices, Inc., 2003 WL 21078026, at *2 (C.D. Ill. 2003) (injuries to business, reputation and good will are all amenable to pecuniary valuation and can be adequately compensated with monetary damages)."
Although this post deals with defamation, the rule also holds true in other areas of the law as well: so long as a plaintiff can be made whole with money damages, a court is highly unlikely to prevent a defendant, by way of an injunction, from continuing what they're already doing.