In my understanding, a sentence of the following form
A requires B, something that may be difficult even when C
means that
A is difficult since a necessary condition B is difficult. While B appears to be easier (to obtain or achieve) in the case of C, it is indeed not.
However, I came across the following sentence in a law paper (Lemley, M. A. (2007). Ten things to do about patent holdup of standards (and one not to). BCL Rev., 48, 149.):
... proving an antitrust violation requires detailed evidence of both causation and intent, something that may be difficult even when, as a policy matter, a patentee should not be permitted to extend its rights.
I don't understand the latter part of the sentence. Could you please help me to clarify the meaning of the sentence. Thank you.
(a little context: a patentee can violate antitrust laws if it abuses its patent rights)