[T]he real irony here is the idea that the government may need to use its antitrust rules to crack down on patent abuse, when the whole reason that there's a "trust" problem in the first place is that patents are a government granted monopoly.
While the US Patent Office has noted it has no intention of dealing with patent trolls (persons or companies who have no intention of manufacturing or marketing their invention but opportunistically enforce patents against other companies), it's good to know the FTC and DOJ are good for something. But Mike brings up a good point, that the whole reason we have a patent troll problem is because we have patents. If the government is handing out monopolies, of course there will be individuals who work to exploit the system. DOJ involvement is just another example of government spending additional resources to combat a government-created problem.
People may argue that patents are necessary to encourage innovation, but that statement ignores the centuries of invention that occurred without a patent system, and also ignores the economic loss caused by patents, both seen -- the money spent on lawyers fighting in court instead of improving their businesses -- and unseen -- the innovations that never occurred at all because of fear of lawsuit.