This piece really is all about the Nortel patents.
Google wanted the Nortel patents very badly but couldn't find enough fellow bidders whose interests matched its own to overcome the concerted efforts of Apple, Microsoft, and others who have a stake in pulling Android down. An interesting analysis of who the winners and losers were in this bidding process appears here: http://www.tangible-ip.com/2011/what-does-nortel-mean-for-th....
Having lost that bid, Google is in a far worse position to defend Android from patent attacks than it ever has been before. Essentially, all of its competitors now have formidable new weapons to use against the Android platform. This isn't so much an issue of "trolls" as it is conventional large players who use patent portfolios as arsenals for both offensive and defensive purposes. Google's enemies are now much more formidably armed as a result of the bidding.
Google therefore hopes to stir the DOJ into doing something about this on the antitrust front. The DOJ is scrutinizing this deal and may wind up imposing conditions that could be vital to Google. Its antitrust chief, Christine Varney, had represented Netscape while in private practice years ago in its antitrust fight with Microsoft and she has publicly expressed concerns about the misuse of patents by trolls and others for anti-competitive purposes (for those with a subscription, see this WSJ piece: http://online.wsj.com/article/SB1000142405270230365740457636...). Quite apart from her personal views, however, it is problematic that competitors can collude horizontally to do a major IP acquisition for what seems like an obvious anti-competitive purpose.
Google is not a "little guy" that might elicit sympathy in battling over the mobile space but it clearly has had its competitors gang up on it in pulling off the Nortel bid. Android will undoubtedly survive this attack but Google is seriously worried about being besieged in this way. In this piece, it is essentially looking to its last best hope in the DOJ for attempting to block this attack by competitors who hope to win by artificial legal means that which they can't win in the marketplace.
Let's hope this gets the scrutiny it deserves.