If Sun Tzu's strategy was a deck of cards (and we are working on that idea, by the way), the wild card in the deck would be a climate card. Certain trends in climate can be foreseen (the winter is cooler than the summer), but events that cannot be predicted can have a dramatic impact on strategic situations. This is why good strategy requires instant reflexes rather than sticking to plans.
In the political season, for example, the trends made this clearly a Democratic year. Generically, a Democratic presidential candidate is preferred over a Republican one by about 15 points. However, events quite apart from the candidate's mistakes (which usually decide these contests) are intruding. Some of these events, such as the improving situation in Iraq, are trends that could have been foreseen, but others, like the decision of the Supreme Court to grant citizen rights to prisoners of war at Guantanamo, are bolts from the blue. Like the earlier decision of the California Supreme court to allow gay marriage (which actually start this week), these changes are object demonstrations of the overreaching of judicial power that are not lost on the public. Americans don't like the idea that unelected judicial appointees can disregard all past legal precedent, the judgment of elected officials in both legislative and executive branches, and, in the case of the California decision, the direct vote of the people, and create their own rules. Event like these, helps the Republicans who have argued for decades against the lack of judicial restraint.
If McCain had any strategic ability (and there has been little signs of it thus far), he would use this decision as the theme for the rest of his campaign. It plays directly into the REFORM message he needs to set up to silence Obama's CHANGE mantra. He should tie it directly to the threat of a national defense run by lawyers rather than the military. Running against lawyers and a corrupt Congress with a REFORM message would be a good way to tack against the wind in this anti-Republican climate.