Americans of all political stripes were distressed by the September 11 attack on the U.S. consulate in Benghazi, Libya, that killed four Americans, including the U.S. Ambassador. But the reaction of the national broadcast networks has been demonstrably and shamefully partisan from the beginning of this story. In the immediate aftermath of the terrorist attack, all three broadcast networks touted the political angle that the events would bolster President Obama — “reminding voters of his power as commander-in-chief,” as NBC’s Peter Alexander asserted on the September 14 edition of Today — while Mitt Romney would be damaged by his supposedly...