If Bush is such a "political cadaver", why does Chavez feel the need to lead such a huge protest?

I guess you are missing the point. The protest was not against the "political cadaver". It was an “anti-imperialist” protest, against what is know as the "American Imperialism"
Chavez reference is about the fact Bush cannot be re-elected and has no support -almost- anywhere. Not from most of Europe, not from China and, obviously, not from most of the American continent. (including the US)
And, sadly enough, Chavez is riding on that political decline and taking advantage of it.

The very fact that Bush cannot be re-elected is a demonstration of how very different he is from Chavez--who is doing everything in his power to get himself permanently installed as president.

Just to make it clear. Don't get me wrong.
I DON"T LIKE HUGO CHAVEZ.
And I dont like the autocracy he is implementing. It's scaring.

I have many Venezuelan friends and I truly suffer for them. I don't believe most of them understand who he is and where they are heading. Having lived under the "Junta" for many years I have a very clear and deep knowledge of what a Dictatorship is.

Also to make it clear:
I DON"T LIKE GEORGE BUSH.

But I like the American democracy.

Abraços,

Kwon