Seventh Circuit Judge Richard Posner issued an opinion yesterday that spells out his interpretation of the continuing violation doctrine in statute of limitations law. The case, Limestone Development Corp. v. Village of Lemont, Illinois, may be found here on the court's website. The docket number is 07-1438. The case is not a copyright case, but no matter, the principles are the same. Judge Posner draws a distinction between the discovery rule, which determines when the limitations begins, and the continuing violation doctrine, which governs the period of time for which damages may be recovered.
The two principles operate in tandem: ordinarily, if a discrete act occurs, in the case of copyright, one has three years from the occurrence of that act to bring suit or else all claims are barred. There is a split on the courts about whether the limitations period runs from the date the infringement occurs (injury accrual) or the date from which a reasonable person would have discovered the infringement (discovery accrual), but the continuing violation doctrine rides on top of either: if the infringement is a continuous one, suit may be brought anytime within three years from the date an ongoing infringement finally stops but, and this is what the opinion yesterday makes clear, damages may be recovered only three years back.
For example, an infringement begins in 2002 and continues until April 1, 2005. You had until March 31, 2008 to bring suit, but if you bring it on that date, your damages will only go back to March 31, 2005. In the past, Judge Posner's views on this have been misunderstood; the current case will dispel that misunderstanding. On one point though his opinion may be misunderstood. He states "The office of the misnamed doctrine is to allow suit to be delayed until a series of wrongful acts blossoms into an injury on which suit can be brought." That statement may be misunderstood to mean that the continuing violation doctrine somehow governs when there is a cause of action. I don't think that is what Judge Posner meant (hence his use of the phrase "a series of wrongful acts"): in all cases, until there is a cause of action, no suit can be brought, and thus the limitations period can't begin to run at all. The continuing violation doctrine also includes instances where there are initial injuries for which the copyright owner could sue if it chose to, but where the copyright owner decides to delay perhaps in the hope the infringement will stop, or, because the injury, though actionable, was small and not worth the candle, and only over time might it become enough of a threat that the expensive mechanism of litigation is justifiable.