In the 1980s, William G. Moore, Jr. was the chief executive officer of Recognition Equipment Inc. (REI), which manufactured a multiline optical character reader for interpreting multiple lines of text.

Many Members of Congress and federal research officers had reservations about the Postal Service's Zip + 4 policy and its intended reliance on single-line readers, in part because of the foreign sources of the equipment.

Moore built on this opposition by lobbying Congress, testifying before congressional committees, and supporting a "Buy American" rider to the Postal Service's 1985 appropriations bill.

Moore alleged that he and REI had received requests from the Postmaster General to be quiet, yet his company proceeded to support its agenda and hired a public relations firm recommended by a Postal Service official.

The first looked into the purported payment of kickbacks by the PR firm to the official who recommended its services, and the second sought to document REI's possibly improper role in the search for a new Postmaster General.

His complaint raised five causes of action, including the claim that the prosecutor and the inspectors had engineered his criminal prosecution in retaliation for criticism of the Postal Service, thus violating the First Amendment.

[7] With the remainder of the case back in District Court, the inspectors moved for summary judgment, urging that because the underlying criminal charges were supported by probable cause they were entitled to qualified immunity from a retaliatory-prosecution suit.

[11] Writing for a five-justice majority, Justice David Souter delivered the Court's ruling that the plaintiff in a Bivens action for retaliatory prosecution must allege and prove the lack of probable cause for pressing the underlying criminal charges.

Second, the causal relationship will be much more complex than in ordinary retaliation cases, because prosecutorial immunity bars the plaintiff from suing the official who directly caused the injury of a retaliatory prosecution.

There is furthermore a long-standing presumption that a prosecutor has legitimate grounds for the actions he takes, supported by the Court's position that "judicial intrusion into executive discretion of such high order should be minimal.

Because the case was at this stage directed only against the instigating postal inspectors, Ginsburg did not believe that the plaintiff—"the alleged victim"—should bear the burden of pleading and proving the lack of probable cause for the prosecution.

She would have instead applied the same burden that the Court of Appeals did, requiring the postal inspectors to show that the U.S. Attorney's Office would have pursued the case even absent "retaliatory motive and importuning."

"So long as the retaliators present evidence barely sufficient to establish probable cause and persuade a prosecutor to act on their thin information, they could accomplish their mission cost[-]free.

Circuit's "more speech-protective formulation," in which recovery remains possible "in those rare cases where strong motive evidence combines with weak probable cause to support a finding that the [investigation and ensuing] prosecution would not have occurred but for the [defending] officials' retaliatory animus."