Faced by the SCOTUS yesterday in the case of Hartman v. Moore,. A nice write up of the case can be found at the SCOTUSblog.
The basic facts are, that Moore is the CEO of a business that makes the scanners that read barcodes. When the US Postal Service decided to go to the zip+4 zip code, the "specs" for reading the barcodes required single line readers. Hartman's company made multiline readers. He spent a lot of time and effort lobbying and advocating against the specification.
As it turns out USPS Board of Governors agrees with him and writes dual line readers into the specs. Turns out bribery played a part in the decision. A number of people are arrested and charged by the Postal Inspectors including Moore. He is acquitted. The question as to whether there was probable cause to prosecute him will probably not be decided by the court ( at the request of both sides). The case is really about whether the Postal Inspectors can be sued for a violation of 42 USC 1983 for retailating against Moore advocacy by arresting him, even if there was probable cause for the arrest.
Plaintiff maintains that any prosecution brought even in part to stifle someone's dissent, is a violation of Section 1983 whether or not there is probable cause to arrest. Even if that is not the primary motive.
Defendant maintains in part that denying summary judgment where there is probable cause to arrest will expose law enforcement agents to expensive litigation that will ultimately fail because there is no retaliatory motive where there is probable cause.
Now on its face most of us probably did't know the whole "zip+4" thing was so controversial as to create a need to retaliate (evidentially it was, take a look at a the write up here.) To an outsider, it seems that the prosecution was probably brought because there was sufficient smoke around the plaintiff to suggest to already suggestible prosecutors that plaintiff, by the voraciousness of his advocacy in the area and his supervisory interest in the firm, must have been involved in this scheme. Hence it would seem that the defense is right and the DC Circuits rule will open law enforcement to expensive discovery before a dismissal can be attained. Of course things are never that easy. Even so this case is not a bright line test.
In the winter of 1991 I had a case of a woman who is protesting the closing of a homeless shelter by the administration of the first black mayor ever elected in a town. She embarrasses the mayor and "shames" him. The Police force in the town looks into the woman's record and finds she neglected to pay a Three($3.00)Dollar fine levied a few years before when she was a vagrant and a prostitute. After she cleaned up her life, she volunteers at the shelter and she forgot about the small nearly insignificant fine. Police go the very next day after her speech at town hall and arrest her for not paying the fine. Now tell me that arrest is not about trying to stifle one's free speech. She was so frightened, that after I won her release and a dismissal (followed by an apology) she refused to sue. I wish she had, maybe That Lawyer Dude coulda been arguing in Washington DC today.