After a brief quiescence, the secret-spilling website WikiLeaks is about to explode again onto the global stage with the impending release of almost 400,000 secret U.S. Army reports from the Iraq War, marking the largest military leak in U.S. history.

Measured by size, the database will dwarf the 92,000-entry Afghan war log WikiLeaks partially published last July. “It will be huge,” says a source familiar with WikiLeaks’ operations, who spoke on condition of anonymity. Former WikiLeaks staffers say the document dump was at one time scheduled for Monday, October 18, though the publication date may well have been moved since then. Some large media outlets were provided an embargoed copy of the database in August.

In Washington, the Pentagon is bracing for the impact. The Defense Department believes the leak is a compilation of the “Significant Activities,” or SIGACTS, reports from the Iraq War, and officials have assembled a 120-person taskforce that’s been scouring the database to prepare for the leak, according to spokesman Col. Dave Lapan.

Superbombs and Secret Jails: What to Look for in WikiLeaks’ Iraq Docs The Afghanistan war logs were just the beginning. Coming as early as next week, WikiLeaks plans to disclose a new trove of military documents, this time covering some of the toughest years of the Iraq war. Up to 400,000 reports from 2004 to 2009 could be revealed this time — five times the size of the Afghan document dump. It’s a perilous time in Iraq. Politicians are stitching together a new government. U.S. troops are supposed to leave by next December. Pentagon leaders were furious over the Afghanistan documents, but the American public largely greeted them with yawns. Iraqis might not be so sanguine. It’s hard to imagine Iraq will fall back into widespread chaos over the disclosures. But they can’t be good for the United States, as it tries to create a new postwar relationship with Iraq, or for the 50,000 U.S. troops and diplomats still over there. We don’t know what’s in the documents. But here’s what we’ll be looking to find in the trove — and some unanswered questions that the documents might address.

“They’ve been doing that analysis for some time and have been providing information to Central Command and to our allies, so that they could prepare for a possible impact of the release [and] could take appropriate steps,” says Lapan. “There are … things that could be contained in the documents that could be harmful to operations, to sources and methods.”

The Iraq release comes at a crucial time for the 4-year-old WikiLeaks, which has been rankled by internal conflict, shaken by outside criticism and knocked off-message by a lingering sex-crime investigation of its founder, Julian Assange, in Sweden. At least half-a-dozen staffers have resigned from the organization in recent weeks, including key technical staff, according to four ex-staffers interviewed by Wired.com. A “scheduled maintenance” of the WikiLeaks website that began September 29 has stretched to more than two weeks.

The beleaguered Assange was cautious in a Sept. 30 public debate at City University in London, where he asked organizers to bar attending journalists and students from recording, photographing or videotaping his appearance.

The controversies dogging the site followed a string of triumphs: a series of high-profile leaks aimed at U.S. and NATO war efforts. In April, the site published a highly controversial classified video of a 2007 Army helicopter attack in Baghdad.

The attack killed two Reuters employees and an unarmed Iraqi man who stumbled onto the scene and tried to rescue one of the wounded. The man’s two children suffered serious injuries in the hail of gunfire. WikiLeaks titled the video “Collateral Murder,” and raised $150,000 from supporters in two days following its release.