Not many people seem to think that the charges are credible. The fact that they are politically motivated doesn't mean that they must be wrong, but at this point there's no reason to believe that they aren't.
Well we know that he vetoed the funding. And we know he's entitled to do that. The question at hand seems to be the intent of the veto... which is rather subjective, to put it mildly.
Isn't this the same DA's office that tried to indict Kay Bailey Hutchison for having her aide pick up lipstick, and the very same that convicted DeLay of those charges of which he was acquitted? Yeah, this seems to be a political hit squad masquerading as a legal authority. For Hutchinson it was because the DA had wanted to be appointed to the senate vacancy she filled. Now it's because this DA refused to quit. It's a personal vendetta, again.
I mean it's not like Republicans don't do this sort of thing, either, but that's besides the point.