During the discussion of the "office deal" statute, some suggested that the plaintiff should plead "not office" as an element, just to be safe. But the effects--taking on the burden of persuasion--weigh against that. The better answer there is for plaintiff to plead the cause of action as she understand it, be ready to fight for that position on the eventual dispositive motion, and be ready to change strategy if she is wrong. That actually captures why we allow dismissal without prejudice--it gives parties a chance to correct mistakes or change course if what they initially believed the law to be turns out to be wrong.
But the discussion also raised a slightly different idea--whether plaintiff in the complaint should anticipate and respond to likely defenses. Someone raised the prospect of pleading a response (e.g. tolling) to an anticipated limitations defense to a complaint the plaintiff knows was untimely filed. This case offers another example--the plaintiffs sued several members of Congress over their votes on legislation giving money to Israel, conduct that everyone knows is absolutely protected from civil liability by legislative immunity under the Speech or Debate Clause.
There are two pieces to this: One is the strategic question of how best to litigate your case. The other is the ethical question of whether filing a complaint the plaintiff knows to be subject to a strong defense (unless the plaintiff has a response or is arguing for an extension of the law) violates Rule 11.
There are two schools on this. On the strategic point, pleading the anticipated response probably will not make that much of a difference. Perhaps seeing the tolling facts in the complaint will cause the defendant not to bother filing the motion, realizing his defense will fail. More likely, the defendant already knew what the plaintiff's tolling argument will be, so this is not news to him. The defense's incentive remains the same--file the motion, make the plaintiff respond, and let the court decide. Same with the Israel suit--defendants will move to dismiss on immunity grounds, regardless of what the plaintiff includes in the complaint.
The Rule 11 concern might play differently. By pleading the response to the anticipated defense, perhaps plaintiff signals to the court that they have done their homework and filed a claim well-grounded in law and fact: They acknowledge the claim was filed after the limitations period but show why the claim is nevertheless timely; they acknowledge that legislators ordinarily cannot be sued but show the planned request for an extension of the law. One can see both sides of this point. For example, the silence of the plaintiffs in the Israel suit suggests they had not really considered the issue at all, making this sanctionable.
But note how this flattens out what should be a sharp distinction between claims (raised by plaintiff) and affirmative defenses (raised by defendant). After all, what if the defendant messes up and fails to raise that affirmative defense? Perhaps the plaintiff--as a matter of ethics and strategy--should be able to plead her claim (as the law defines it); put the onus on the defendant to raise his proper defenses; and respond as necessary?
No right answer. Strategic points to think about.