The US is apparently convinced that whistleblower Bradley Manning, who was arrested two weeks ago, did indeed hand over 260,000 US diplomatic cables concerning the Middle East over to Wikileaks....Gee, that sounds familiar. Remember when the US was apparently convinced that Saddam Hussein was in cahoots with Al-Qaeda and had Weapons of Mass Destruction that he could toss across the unfortified Iraq-US border in, like five minutes? (We'd have liked to have Mr. Hussein's cooperation in this, too.) Remember when the US was apparently convinced that the American scientist Wen Ho Lee had given our nuclear secrets to the Chi-coms? (Cooperation, Dr. Lee?) For an oldie but goodie, remember when the US was apparently convinced that Ho Chi Minh was a willing puppet of the Russkies? (It's in your own interests to cooperate, Mr. Ho.)
American officials would not discuss the methods being used to find Assange, nor would they say if they had information to suggest where he is now. "We'd like to know where he is; we'd like his cooperation in this," one U.S. official said of Assange.
Right now the US is also apparently convinced that Iran has Weapons of Mass Destruction that it can toss across the flimsy, unguarded Iran-US border with nothing to protect us. (Also that Iran is moving toward a military dictatorship, which the US of course deplores.) Also that Hamas seized control of Gaza in a brutal coup against the Palestinian authority.
This doesn't mean, of course, that the US is never correctly convinced about anything. But how do you tell? Generally it's wiser to assume that the American government (like any government) is lying at the outset.