Some states have a statute of limitations on rape in the United States because of the availability of evidence and to encourage the parties to promptly litigate their claims. Those in favor of the time limits believe it's the most fair for defendants to respond to claims when memories are fresh and evidence is available.
However, in the wake of criticism over the inequity of such limitations for victims, some states are making efforts to repeal these statutes of limitations to allow victims access to justice.