In his New York Times op-ed piece, "The Case for A Cover-Up," John Tierney explains why:
. . . Congress has finally sprung into action. It has bravely promised to investigate the situation. Unfortunately, the members haven't figured out exactly how, because Democrats want it to be done by outsiders. They say the Republicans will turn it into a cover-up. But why does that bother the Democrats so much? Shouldn't members of both parties want to cover this up?Read the whole thing to find out why Tierney thinks so.