It's not about them stopping it, it's a matter of them having the integrity required to either defend the decisions that they made *not* to oppose waterboarding, or to castigate themselves for their failure to do so.
I'd respect either much more than pretending that they aren't responsible for their decisions after they turned out to be unpopular with their base.
The Republicans own the House, the Senate and the White house and the Democrats are STILL responsible for what went wrong.
Democrats are really bad people with incredible powers.