That's fine and dandy, but in order to marshal public support, a president needs to effectively use the bully pulpit - the classic example being Ronald Reagan, who fought a press that was just as hostile. Tony Snow is right - you have to define yourself and stay ahead of the press.
Bush has done and continues to do that. You cannot take a single-time point snapshot and claim that Bush's support has collapsed. Even this port deal has yet to fully play itself out. I agree that Bush needs to make a better public case for this decision and I think he will. Of course, it won't satisfy the pitchforkers, but what could he do that would?
As far as Reagan is concerned, a lot of his popularity during his term of office is retrospective. Have a look at this interesting piece More Gloss for the Gipper. Reagan only ranks in the middle of modern Presidents in terms contemporaneous approval.
Outside of the 9-11 aftermath, when the press and Bush were on the same page for awhile, I don't ever remember Bush being ahead of the press. Ever. One of my pet peeves with Bush administration, total lack of public relations. It all starts at the top. I know some people would like to overlook the press completely, but that isn't possible. Ignoring them doesn't help either. Bush and Cheney have been poor communicators in many respects, failing to advance their message and keep pounding it home. Overall, however, nothing approaching total failure.