If events after the filing of the lawsuit have ended P's injury, the case must be dismissed as moot b/c P must present a live controversy, though non-frivolous monetary damages claims will keep the case alive.
Exception 1: the wrong is capable of repetition but evades review b/c of its inherently limited time duration, i.e. abortion.
Exception 2: voluntary cessation by D who can easily start again
Exception 3: class action suits, as long as one person's claim remains unresolved