Well, it's a lot more complicated than that. Actually, Scooter Libby ended up as the fall guy. Poodle Blair, although all smooth and plausible, was much more bumbling in terms of practical politics. He got up on his hind legs in front of the Commons and said Hussein had weapons of mass destruction on missiles which could be launched in 45 minutes. That was, of course, bullshit, and it eventually torpedoed Blairs career.
But Bush and his forty thieves of Baghdad were a much more cagey lot, and much smarter in terms of practical politics. Bush did not actually say that Hussein had weapons of mass destruction and was implicated in September 11th, and only suggested that Hussein was trying to get weapons of mass destruction in his State of the Union address in 2003. For that, he had the "evidence" of a CIA report. However, the report was discredited by the husband of a CIA agent before
it was sent off to the National Security Agency (then run by Condaleeza Rice). Not only did Bush have "plausible deniability" about the accuracy of the report, at the time of the State of the Union report, he probably did genuinely believe it was accurate. Even then, he wasn't saying the Hussein had weapons of mass destruction, but only implied that he was attempting to acquire them. This was based on the "yellow cake" report.
A CIA operative named Valerie Plame (Valerie Plame Wilson) was married to a former U.S. Ambassador who was very knowledgeable and experienced in African matters. When a story came out that the Iraqis had attempted to get yellow cake uranium in west Africa, her husband, Joseph Wilson, was asked to inquire into the matter. He did, and in March 2002, ten months before the statement in Bush's State of the Union address, he came to the conclusion that there was nothing to the story. But, apparently, someone at NSA (many people think it was Rice) didn't like the answer, and the report was bounced back to Central Intelligence, who took the hint, and reported that Hussein had tried to acquire uranium in Niger. Then Colin Powell (then the Secretary of State) went off with his bullshit to the UN--which in the event didn't do much good.
Three months after the invasion of Iraq, Joseph Wilson published a piece "What I Didn't Find in Africa," and set off a fire storm. So Scooter Libby, right hand man to the Vice President, Dick Cheney, then revealed to a journalist named Novak that Wilson's wife, Valerie Plame, was a CIA operative. This was a violation of the law, and was seen as "punishment" for Wilson's published article, as it ended her CIA career. Libby was eventually successfully prosecuted for it. So he was the only fall guy.
At their most egregious, the Bush administration made to formal claims about Hussein and weapons of mass destruction or involvement in September 11th--none which could not fall under "plausible deniability." Bush could always claim that he had spoken in good faith in his State of the Union message--and he may well have done. Cheney went around the country making suggestive remarks, at one time saying "We know what palm tree they're parked under"--but he did so at an event at which he knew he was being audio or video recorded. Plausible deniability, it came down to a he said-he said between him and one reporter.
Blair was much stupider. Bush got re-elected as a "War President," and even though he sank to the lowest low by the end of his presidency, he left office with this skirts clean. He was always able to plausibly deny that he knew the intelligence had been fudged. Even Condaleeza Rice was able to skate, because even it was revealed that administration figures had pressured the CIA to produce a report implicating Iraq, there was no documentation that the administration figure was her. As far as practical politics go, Bush's administration was pretty slick.