Yes, I know what Posse Comitatus is. And it had zero application in this situation. Your comment about it is a red herring. The Louisiana National Guard should have been used for law inforcement purposes, and National Guard from other states and other US forces should have been used for non-law enforcement kinds of support.

Bush wants to make Posse Comitatus an issue in this context because he's a big government, more power for the executive branch kind of guy. He wanted to use it to enlarge the government, and his power. And he wanted to further erode states' rights. That's why he's a radical and not a conservative.