"If people can’t trust not only the executive branch but also don’t trust Congress and don’t trust federal judges..."

"... to make sure that we’re abiding by the Constitution, due process, and rule of law, then we’re going to have some problems here," Obama said.

Lawprof Steve Shiffrin (at the Religious Left Law blog) says:

The problem is that federal judges ran away from the Constitution years ago on this very issue, and the President’s characterization of this program as a “modest encroachment” on privacy shows that he either lacks integrity or he has an impoverished conception of privacy....

The notion that we should trust federal judges to uphold the Fourth Amendment is impossible to take seriously.  As the Supreme Court stated in United States v. Miller, “This Court has held repeatedly that the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities, even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in the third party will not be betrayed.” This third party principle permits the Federal Government without probable cause or even reasonable suspicion and without any notice to you: to get all of your bank records, a record of who you have sent mail to and received mail from, and who you have phoned and who phoned you...  The claim is that we have no reasonable expectation of privacy in material we have exposed to a third party like a bank, a post office, or an internet provider.  This line of reasoning is worthy of a totalitarian state.....

Another way of putting that is to say we might be able to trust the judges to follow the existing legal doctrine, but the 4th Amendment doctrine doesn't protect us as much as you might think.