Voldemort is shown in a business suit in at least one scene.
He wears a suit when Harry is hallucinating. When we actually
see him, he's wearing robes. I took the suit to be a symbol of Harry's paranoia: Seeing Volemort everywhere, lurking in every shadow, every stranger possibly being Voldemort in disguise. Seeing it as a metaphor for "corporate malice" is quite a stretch, I think.
Fudge was doing what Bush is accused of doing - trying to set up a totalitarian state.
Bush is trying to set up a totalitarian state... Um, right, okay, and Bush also sacrifices a changeling child on an obsidian alter every second Tuesday of the month in order to channel the spirit of Hitler. Cheney draws the necessary pentagrams with stolen crude oil.
But I don't think Fudge was trying to set up a totalitarian state, or set up anything, really. His sin is not his desire to dominate, but rather his refusal to acknowledge the facts. His intentions are good: He wants to preserve the freedom and safety of the wizarding world, but he is too fearful and weak to take the necessary steps to get that done. He'd rather pretend that everything is fine and hope that Voldemort will just go away if everyone avoids looking at him. When Fudge gets nasty is when other people refuse to accept his delusion. Because it is a delusion, it cannot withstand criticism, and hence criticism becomes a crime.
That is certainly an important theme in the HP series: Wrong ideas cannot bear criticism, and so, reason being against them, those who cling to delusions must resort to force.
Anyway, what I said was that Voldemort=Osama and Bush=Fudge are not compatible analogies. If you say Bush=Fudge, then Voldermort has got to be somebody else. But I doubt Rowling meant to comment on any particular person in her writings. I don't think she was going for allegory.