In federal civil cases, the attorney (or unrepresented party), by presenting to the court
a pleading, written motion, or other paper, certifies that to the best of her knowledge,
information, and belief formed after an inquiry reasonable under the circumstances:
(i) The paper is not presented for any improper purpose (harassment, delay, etc.);
(ii) The legal contentions therein are warranted by existing law or a nonfrivolous
argument for the modification of existing law or the establishment of a new law;
(iii) The allegations and factual contentions either have, or upon further investigation or
discovery are likely to have, evidentiary support; and
(iv) Denials of factual contentions are warranted on the evidence or, where specified,
are reasonably based on a lack of information and belief.
The certification applies anew each time an attorney or unrepresented party “later
advocates” a position contained in a pleading, motion, etc. Thus, a paper that was not
sanctionable when first presented may become sanctionable if the attorney or party later
advocating a position contained in the paper has since learned or should have learned
that the position no longer has merit.