Why Don't The Fed's Nationalize Arizona?

So, far, the federal government, with the approval of President Obama and Harry Reid have filed a lawsuit against Sheriff Joe Arpaio. http://www.foxnews.com/politics/2010/09/02/justice-dept-sues-arizona-sheriff-civil-rights-probe/ This is in conjunction with the two previous lawsuits against the state of Arizona and against a local school district. Also take in to account that there are parts of Arizona that are basically off limits to locals and visitors because it has been over run with illegals and drug and human smugglers. This order is from the Feds.
Most of the rural land is owned by the BLM, so they already have a head start.
Clearly, the Fed's who live in Washington D.C. think they can do things better that the people who were elected by the citizens of Arizona. So why don't the Fed's just nationalize Arizona and let them deal with Arizona's problems? I am sure Obama and Reid and Pelosi and the other morons in D.C. can do a better job running Arizona than the elected officials down there. Just like the D.C. morons are doing such a better job ruining the country since they were elected to power.