LONDON — As the suspected source for the biggest intelligence leak in American history faces his first hearing Friday, U.S. prosecutors have their eye on another prize: the man who disclosed the documents to the world.
When WikiLeaks' spectacular disclosures of U.S. secrets exploded onto the scene last year, much of Washington's anger coalesced around Julian Assange, the silver-haired globe-trotting figure whose outspoken defiance of the Pentagon and the State Department riled politicians on both sides of the aisle. Pfc. Bradley Manning, long under lock and key, hasn't attracted the same level of ire.
The pair's fates have been intertwined, however, even if the Australian-born WikiLeaks chief says he didn't know the private's name until after news of his arrest emerged in June 2010. Manning's alleged disclosures put Assange at the epicenter of a diplomatic earthquake.
Assange in turn has worked energetically to drum up support for the imprisoned soldier — all while emphasizing that the way his anti-secrecy site was set up meant he could not be sure if Manning was his source.
U.S. investigators have been scrutinizing links between the two as they explore the possibility of charging the Australian with serious crimes under U.S. law. A Virginia grand jury is studying evidence that might link Assange to Manning, but no action has yet been taken.
In chat logs recorded by Adrian Lamo, the hacker who turned Manning in, the 23-year-old private allegedly poured his heart out, laying bare his disillusionment with the military and his decision to ship mountains of classified material to Assange. In the logs — which the military says are genuine — Manning tells Lamo that he'd "developed a relationship with Assange" and hinted at instant messages swapped via a server maintained by the Germany-based Chaos Computer Club.
But even according to the logs, Manning and Assange do not seem to have learned very much about each other. "He won(')t work with you if you reveal too much about yourself," Manning is quoted as having said.
At least one media report suggested that prosecutors have struggled without success to flesh out the purported links between the pair. NBC News, citing unnamed military sources, said earlier this year that officials had turned up no evidence of direct contact between Assange and Manning.
In any case prosecutors face formidable obstacles. Experts say that a prosecution under the century-old Espionage Act would risk criminalizing practically any form of investigative journalism. A conspiracy charge, which some have floated as an alternative, would also be tough to prove.
"If Manning steals a bunch of information, and gives it to Julian Assange, I think that would be very difficult to show that that was a conspiracy," said Benjamin Wittes, a senior fellow at the Brookings Institute. Even if it turns out that Assange had, hypothetically, pushed Manning to divulge the documents, Wittes said it would still be hard to distinguish that from a traditional reporter trying to work a source.
"Is that any different in principle from the relationship between Deep Throat and Bob Woodward?" he asked, referring to the source behind the Watergate scandal and one of the reporters, Woodward, who broke the story.
Inquiries into Assange and WikiLeaks are ongoing. The grand jury has been investigating for more than year and could continue for months or even years longer. Witnesses have been called, though the identities of most are unknown.
A Manning supporter, David House, refused to testify when he was called in June, citing his right against self-incrimination. House said nearly all the questions posed to him centered on Manning. He said he was not asked about Assange.
There remains pressure to haul the computer hacker-turned-openness advocate before an American judge.
Both Democratic Vice President Joe Biden and Republican presidential hopeful Newt Gingrich described Assange as an information-age terrorist, with Gingrich saying that Assange should be "treated as an enemy combatant." Others have been even more explicit, with pundits including former vice presidential candidate Sarah Palin calling on American officials to hunt him down.
The bloodthirsty rhetoric may have receded since last year, but the otherwise deeply divided U.S. political establishment remains nearly unanimous in its hostility to Assange.
"At a time when the political parties are polarized, WikiLeaks succeeded in uniting them," said Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists.
No matter what happens at Manning's court martial, Assange faces a host of other legal and financial problems.
His WikiLeaks website operation is running out of money and could close by next month. The British Supreme Court could rule on whether to extradite him to Sweden, where he is wanted on sex crimes allegations, as early as next week.
He has spent the last year fighting extraditon from a wealthy supporter's country estate in southeastern England, where he lives under virtual house arrest.
Matthew Barakat in McLean, Virginia and Richard Lardner in Washington contributed to this report.