Here is a WaPo/ABC poll, and one from CNN/USA Today/Gallup on the effects of Powell’s speech to the Security Council. They are oddly confusing, if not contradictory. Yet, Oxblog makes sense of them, in a few paragraphs. Here are a few good lines from Oxblog, the rest is also worth reading.

"What neither Gallup nor a WaPo storyabout the polls points out is how remarkable it is that both
Bush’s State of the Union speech and Powell’s UN address significantly increased support for an
invasion. This sort of double-bounce has almost no historical precedents."