The cumulative effect of the “non-parallel” aspects of district court and reexamination proceedings is profound.  It is the authors’ perception that broader claim construction used by the PTO, combined with the lack of any presumption of validity and skilled decision makers, results in far easier prior art validity challenges.  Moreover, the CRU often rejects all of the claims in the first Office Action and puts the burden on the patent owner to prove the patentability of the claims, even if the claims have been subject to extensive prior art attack in prior court actions.