I think John Scalzi puts his finger on it (I just hope he washes it afterward):

The fundamental problem with the Bush Administration is that it appears to be working from the position that being right excuses being incompetent. This presents two problems. First, when it happens that the administration is right, as it is in wanting Saddam removed at the earliest available opportunity, it blunders about being right in such a way that others would prefer to be wrong rather than to be in its company.

This is what I find particularly galling about this administration's incompetence. They are making the world less safe because they are allowing their obsession with Saddam to destroy our close ties with our allies. And, in the end, they may actually make the world safer for Saddam in the process if the growing anti-war movement manages to derail the Bush juggernaut (still possible, though highly unlikely).

I fear for the fact that the Bush administration wants to promote the development of hydrogen engines; if it goes about promoting the program like it's handling Iraq, we'll be stuck sucking oil out of the Arabian peninsula for another three centuries.

Which could, of course, be the whole point. If you can't fight something you don't like, adopt it whole-heartedly, and then destroy it from within. It's kind of the Bill Gates approach to national leadership. It's also how viruses work.

It's never an especially good time to have an incompetent rubbing against the furnishings of the Oval Office and marking it as his territory, but some times are better than others. Warren Harding was a monumentally bad President, but he was also President during a time when he (or his thieving cronies, which is more to the point) couldn't do a tremendous amount of lasting damage. Alas, today is not one of those times, and in any event Dubya and his pals aren't the sort to be content with mere graft. They're not crooks, they're ideologues with a deep and abiding moral clarity, both economic and religious, that's dreadfully inconvenient to those of us who prefer that moral clarity not trim away our budget surpluses or, come to think of it, so many of the basic freedoms afforded to us in the Constitution.

Here I disagree with John. This administration is both incompetent and corrupt (being corrupt involves more than just committing crimes). Which is why it will easily rank as one of the worst in U.S. history. But, when you add in the ideological sense of "we're right and you're wrong and we will screw the pooch if it is necessary in order to prove it", then you reach a level of awfulness that no administration, to my knowledge, has ever reached. Grant may have been corrupt. Buchanan may have been incompetent. But Bush is corrupt, incompetent, and inimical to the very idea of America.

Be that as it may, it is my government. When I agree with it, I want it to succeed. When I disagree with it, I at least want to get the feeling that even if I disagree, some thought went into the government's opposing position. The tragedy of the Bush administration is that it provides neither of these. Its total incompetence means that it fails when it's right, and it fails when it's wrong. The best you can say about Dubya and his people is that at least they're consistent.