Within hours of the disclosure that federal authorities routinely collect data on phone calls Americans make, regardless of whether they have any bearing on a counterterrorism investigation, the Obama administration issued the same platitude it has offered every time President Obama has been caught overreaching in the use of his powers: Terrorists are a real menace and you should just trust us to deal with them because we have internal mechanisms (that we are not going to tell you about) to make sure we do not violate your rights. Those reassurances have never been persuasive — whether on secret warrants...