As contentious as such hearings are bound to be, having Congress tied in knots over this matter is far superior to leaving the Democrats unoccupied enough that they're easily able to ruin the health care system through their efforts at "reform." Some on the left have asked for such hearings; now, either the Democrats can grant them or they can be charged with "covering up" for the oh-so-evil Bush administration.
Let's see with whom the President sides -- those in favor of full disclosure, or those in favor of "moving on." He'll be forced either to put his agenda on hold while this gets sorted out, or else further alienate his core constituency on the far left.
What's more, Republicans only have reason to fear such hearings if they suspect that the Bush administration or the CIA tortured gratuitously. I believe that the facts will reveal that this was not the case -- that EIT's were used only in specific circumstances and for the most part helped save American lives.