I have been saying for five years now that this was Bush's single worst mistake.
The news media would have screamed, of course, and all the liberal bureaucrats and backstabbers who were ousted. But it should have been done right at the start.
I also mentioned Machiavelli's very helpful advice on this subject. If a ruler has to do something that will make him unpopular (like killing his enemies), then he should do it early, do it thoroughly, and do it all at once. Get all the bad news out at once, and then the rest of your term will be one long relief. People will be delighted that you are no longer killing them--or firing them.
King James I, a political idiot but still evidently smarter than Bush on this matter, wrote some advice to his son. Among other things, he told him that the best way to start off his reign was to hang a few people. That would sober his enemies, make people more obedient, and, over the course of his whole reign, would actually result in his having to hang a lot fewer people, because it would teach them to be careful.
Kind of like PATCO?