Photo by AP Photo/Pablo Martinez Monsivais U.S. President Barack Obama has been enjoying a surge of popularity after passing health care reform, finalizing a new nuclear arms treaty with Russia, and maintaining a 55% brackets approval rating. But that good will evaporated for some D.C. residents today when President Obama, taking the mound to throw out the first pitch to mark Opening Day, donned a White Sox cap. Isn’t it enough that Phillies fans have…