If you look at history, you can see that there is essentially a blueprint for turning an open society into a dictatorship. That blueprint has been used again and again in more and less bloody, more and less terrifying ways. But it is always effective. It is very difficult and arduous to create and sustain a democracy - but history shows that closing one down is much simpler. You simply have to be willing to take the 10 steps.
As difficult as this is to contemplate, it is clear, if you are willing to look, that each of these 10 steps has already been initiated today in the United States by the Bush administration.
Rest of Wolf's article here, and here she delivers a talk on the same issue, ie the closing down of a democracy.