Patent litigation is a two-front war fought over the words of the claims. Infringement asks whether the accused product or process practices every limitation of an asserted claim, literally or under the doctrine of equivalents. Validity runs the other direction: the defendant attacks the patent as anticipated, obvious, or inadequately described. Because an issued patent is presumed valid, invalidity must be proven by clear and convincing evidence, a higher bar than the preponderance standard that governs infringement -- an asymmetry that shapes strategy throughout.

Everything pivots on claim construction. In a dedicated Markman proceeding, the court interprets disputed claim terms as a matter of law, and those constructions frequently decide both infringement and validity at a stroke. Parallel proceedings compound the chess match: a defendant can challenge the patent at the Patent Trial and Appeal Board through inter partes review under a different standard and on a faster clock, often seeking to stay the district court case. Remedies range from reasonable-royalty or lost-profits damages to enhanced damages for willfulness and, in limited circumstances, injunctive relief.

The Markman ruling is the true settlement trigger: because construction so often resolves infringement and validity together, cases cluster their bargaining around it. The clear-and-convincing standard for invalidity gives patent owners a defensive edge, while the availability of a faster, lower-standard PTAB challenge gives accused infringers a counterweight and a stay lever. Enhanced-damages and fee-shifting exposure for willfulness or exceptional cases sharpens the tail risk on both seats, so parties negotiate against skewed outcome distributions rather than a clean midpoint.