In 1781, the Continental Army won a decisive battle in the War of Independence by employing a daring pincer movement, in which the Continental forces were tactically divided so as to attack the advancing British from two flanks.
The same tactic is being employed as we speak in the ongoing Vringo (VRNG) vs. Google (GOOG) patent infringement trial. As the trial has unfolded, it has become clear that Vringo's legal team has decided upon a pincer movement of sorts by deploying its liability expert, Dr. Frieder, to attack Google on one flank, while reserving its validity expert, Dr. Carbonell, to attack Google from an opposite flank after Google rests its case.
Vringo's strategy of "bookending" its experts is highly appropriate under the circumstances. During Vringo's case in chief, it bears the burden of proving Google's infringement, and so calling Dr. Frieder to testify as to this issue was necessary in order to establish itsprima facieliability case. During Google's case in chief (which is proceeding as we speak), it has two objectives: 1) defend against Vringo's infringement claims, and 2) prove that the Lang patents are invalid due to the prior art. Google has placed all of its eggs in one basket, choosing to use Dr. Ungar as its expert on both issues. Once Google rests its case, Vringo will "have the last word," so to speak, by presenting Dr. Carbonell --who will testify after Google's presentation has already been completed.