Folks, we are witnessing a very special moment in history: the birth of a Known Fact™.
Known Facts™, as you may well know, are things which are not really facts at all, but are clung to by the left with all the force and tenacity of runaway religious fervor. It is common for conservatives to express amazement at how liberals come to believe in ridiculous things like War-for-Halliburton, and even more, to simply assume that the rest of the world shares in their delusion. If you ever ask a liberal to provide you with evidence for one of these bizarre conspiracy theories, they will likely respond in amazment, "Everyone knows that - it's a Known Fact™ that (Bush lied, we went to Iraq for oil, or whatever the liberal conspiracy theory du jour might happen to be). It's less often analyzed how these Known Facts™ come to be, but the recent bru-ha-ha over the NSA wiretaps is slowly but surely giving birth to another Known Fact™ - namely, the Known Fact™ that Bush broke the law by authorizing these NSA wiretaps. We are therefore provided with a unique opportunity to study the phenomenon as it occurs.
Phase one generally involves the media. Whenever a story comes out that might possibly shed negative light on a Republican, and most especially George W. Bush, you can expect the media to sensationalize the information and interpret what little is known in the worst possible light. Thus, a program in which computers sift through the international telephone calls of known Al Qaeda operatives for certain key words gives birth to ludicrious headlines like, "Bush authorizes spying on Americans," complete with the obligatory "Specter calls for investigations."
With Phase two, the partisan liberals (insofar as they are distinguishable from the media) kick in, as they set about to prove this interpretation of the facts. After all, this seems like the kind of thing they'd expect from Bush, it's consistent with the picture they have painted in their own minds of "King George," and so the more intellectually lazy liberals will simply assume it is true without further evidence and move on with their lives. Some of the more industrious liberals will actually take things a step farther, and try to produce evidence to back up their claim. Thus, you have folks like Glenn Greenwald, who, so far as I can tell, is the only lefty even trying to produce evidence of any actual lawbreaking by Bush anymore.
Phase three begins when disinterested experts like Richard Posner and Cass Sunstein (who is, by all rational accounts, a giant in liberal legal circles) take the time to actually do real research into the situation. Posner has actively declared that the Bush administration's policy has not gone far enough in gathering domestic intelligence, and even Sunstein is forced to admit that the Bush administration's justification for this program is "plausible," and that if FISA conflicts with the President's Article II authority, then FISA itself might just be unconstitutional!
For most rational people, at this point, the argument dies and they move on with their lives. However, the media is generally never bothered to print a retraction, and certainly nothing on the level of the furor that was generated over the original story. The lazy liberals continue to repeat the contentions of the few liberals who did any homework whatsoever, even after that homework has been largely discredited - discounting all contrary evidence as part of a NeoCon PNAC conspiracy that probably involves the Freemasons and Knights Templar if you only dig down deep enough. The fact that you have to shoehorn guys like Posner and Sunstein into such a bizarre conspiracy group is irrelevant - the only important fact is what everybody "knows" really happened - the evil Chimpy McBushitlerburton broke the law and spied on American citizens. They "know" that this happened because it is consistent with their neverending, burning hatred of Bush, and their vision of him as the boogeyman who lurks in their closet, just waiting to throw all Democrats and Liberals in jail and send them off to forced labor for Halliburton in the West Texas desert.
What do you mean, you want evidence? They're only telling you a Known Fact™.