The already existing rule 11 penalizes baseless litigation. The modifications in this bill makes sanctions obligatory rather than optional, removes escapes for what would be sanctionable actions, and expands the range of sanctions. The clause in question strikes me as redundant, because existing rule 11(b)(2) says of the action that
(2) the claims, defenses, and other legal contentions are warranted by
existing law or by a nonfrivolous argument for extending, modifying,
or reversing existing law or for establishing new law;
Without either of these clauses, sanctions could be imposed on a bright guy who comes up with a new legal argument that actually works, which I think is clearly contrary to the intent of the original rule. Such a clause is a way of telling the courts "No, that is not the legislative intent". But the existing rule already covers that outcome.
It may be that the added sanction "striking the pleadings, dismissing the suit, or other directives of a non-monetary nature..." was thought to potentially threaten "creative lawyering", but again that seems to be already covered by 11(b)(2). The words "assertion or development of new claims, defenses, or remedies under Federal, State, or local laws, including civil rights laws, or under the Constitution of the United States" differ from "nonfrivolous argument for extending, modifying,
or reversing existing law or for establishing new law", but they seem to describe the same kind of facts. Perhaps a historical reading of the various versions since 1983, especially related to the advisory committee notes, would reveal more precisely why this is necessary.