Click here to access article from Washington's Blog.
Although I only scanned this article, I don't see that this blogger answered the question posed in the headline. But, he does provide considerable evidence of the construction of a police state in the US since 9/11 which was used to justify the construction. This suggests that the construction of the police state is the answer. This was only a means to an end.
Permit me to offer a succinct answer. The real reason is that the shadow government
represents a capitalist class that has since WWII painstakingly constructed their shadow government because they no longer wanted to be faced with all the messy complications and expense of maintaining a pseudo-democracy. The latter interfered with their agenda of world domination under the control of financial and industrial corporate elites.
Recall that they have spent so many years and money maintaining a pseudo-democracy whose propagandists espoused self-determination, "democracy", elections, freedom of the press, human and civil rights, etc, and now these ideological structures function to inhibit their designs for world domination. They expect eventually that regular citizens will wake up and fight back. Thus, they have prepared all the mechanisms of a police state to guard against this: full-spectrum surveillance, a huge prison complex, the elimination of all constitutional impediments that this article documents, and the establishment of a national, militarized police force under the direction of the Department of Homeland Security.