"Poll: Two-thirds of Americans support Bush ultimatum"
Quoted directly from that CNN report (emphasis mine): "With the nation on the brink of war, two-thirds of all Americans say they approve of President Bush's stark ultimatum to Iraqi leader Saddam Hussein and say they believe he did all he could to resolve the crisis diplomatically, according to a new CNN/USA TODAY/Gallup poll."
A poll of n people is just that; a look at the opinions of those n people. A poll is not, however, a reflection of what "all Americans" think. I wasn't polled for this, no one I know was, and so right there is isn't 'all Americans'. 2/3 of those surveyed may have supported Bush, but we don't know that it's 2/3 of 'all Americans'.
Polls, and statistics in general, can easily be manipulated to obtain whatever result you want. In this case, we don't know 2 things, first, what the question asked of these people was, and second, just what sort of demographic was targeted. It's very possible, and quite likely, that either of these factors here could show a bias toward obtaining that result.
For some reason, this (satire) seems all to appropriate given the media's coverage of the world lately.