Neither the Congress nor the courts have proved effective checks against an aggressive executive branch. As the decision by the Surpeme Court not to hear the ACLU case against the illegal wiretapping due to lack of standing shows, the cloak of secrecy the Bush administration has thrown around evberything questionable it does makes any actual oversight impossible.
How "conservatives" can be comfortable with this is absolutely beyond me. Maybe when the Democrats control eveything the GOP will remember their principles.
Evidently the only defense left for the Constitution is the voters, who can save the rule of law by electing the opposition. I have every reason to believ that Obama respects the Constitution and will undo some of the worst of the abuses, but it's not reassuring that it would take the executive branch to undo the exec's abuses. It's a serious breakdown of the principle of checks and balances and should be a concern to everyone who supports republican government.