"Justify"? That's what's wrong with congress these days and, of course, the media.
Congress feels there's wrong and right reasons for illegal wiretaps. Results speak louder than words. Congress isn't, and hasn't argued it simply on the grounds of the constitution. That would make it more difficult to justify the changes they're going to have to make so that their results are justified.
The sad thing is that most people think this is a party based mentality.