1.     102  novelty!!!  try to show it wasn’t novel
2.     103  obvious!!! try to show it was obvious (this can always be argued b/c it’s somewhat subjective)
3.    disclosure statements; duty of candor with the patent office; “they knew about his prior art and they didn’t disclose it to the patent office;”  even if that wouldn’t bar their claims if a rzbl patent examiner might have considered it material, the patent is invalidated (all claims!)
4.     112  enabling disclosure:  their specification did not enable!  we tried their specifications and it didn’t work; we encountered all these problems;
5.    best mode:  you must show what you believe is the best version of your invention, not just any version; especially hard to show this was best mode if you’re now made improvements; did you know about that before???  if so, invalid!  Tell clients to keep good records of improvements.
6.    maintenance fees not paid
7.    doctrine of equivalents:  P may say my claim calls for a bungee cord and the D is using a rubber band; P says “means for” & doctrine of equivalents
8.    prosecution history estoppel:  (aka file wrapper estoppel)  if the patent holder, during prosecution of the patent, narrowed the claim in order to get the claim allowed over the prior art, the patent holder is now estopped to go upstream to the more general thing!
9.    “means for” only = things that are the same and or equivalent to the thing in the specification; the D can argue that magnets are not “means for” equivalents with rubber band things.
10.    patent misuse:  patents, TMs and CRs are exceptions to the free enterprise system; if you misuse a patent (try to expand it beyond legal exception to free enterprise) you lose it.    Example: everyone wants this patent; we only sell if they agree to buy all their raw goods from us as well.  This is “tying” and is an antitrust violation and is per se patent misuse.
11.    multiple patents on a single invention; one invention = one patent; it’s best to have multiple patents b/c then you get two bites at the apple; juries like to compromise.