Check out this article from Media Matters:

Despite the obvious signs it exists — and has for nearly 20 months — the pervasive buyer’s remorse that hovers around President Bush’s second term, as measured by public opinion polls, remains off limits for the press. The topic is all but banned from polite discussion among elite Beltway press players who seem to be deeply invested in the success of the Bush administration.

Some good historical context for Bush’s alleged 42% “bounced” rating is presented by this article.