Uploading of more than 700,000 files to WikiLeaks had no significant strategic effect, analysis finds, putting into context the severe punishment she received

The publication of hundreds of thousands of secret US documents leaked by the Aarmy soldier Chelsea Manning in 2010 had no strategic impact on the American war efforts in Afghanistan and Iraq, a newly released Pentagon analysis concluded.

The main finding of the Department of Defense report, written a year after the breach, was that Manning’s uploading of more than 700,000 secret files to the open information organization WikiLeaks had no significant strategic effect on the US war efforts.

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The belated publication of the analysis gives the lie to the official line maintained over several years that the leak had caused serious harm to US national security.

It also puts into context the severe punishment that was meted out to the soldier – 35 years in military prison, the harshest sentence in history for an official leak. And it raises questions about the continuing investigation by the US justice department into the WikiLeaks founder, Julian Assange.

The conclusions are contained in the final report of the information review task force that the DoD set up in the wake of the Manning leaks to look into their impact in the hope of mitigating any damage. The report was obtained by BuzzFeed’s investigative reporter Jason Leopold under freedom of information laws.

The report is so heavily redacted in the form it was given to Leopold that its original 107 pages have been reduced to 35. Nonetheless, some key findings can still be gleaned from it.

On Afghanistan, the review finds that there was no “significant ‘strategic impact’ to the release of this information”.

Similarly, the study of the impact on the Iraq war concludes “with high confidence that disclosure of the Iraq data set will have no direct personal impact on current and former senior US leadership in Iraq”.

Beneath these headline observations, the defense department review does raise concerns about the fallout from the documents, which were initially published by a consortium of international news outlets led by the Guardian. It says that “lives of cooperative Afghans, Iraqis, and other foreign interlocutors are at increased risk”, and it notes that 23 serving US military personnel were warned in advance of publication that their full names and social security numbers were included in the files.

The Guardian and the other international outlets involved in the consortium, including the New York Times and Der Spiegel, published selected documents from Manning’s trove having removed any sensitive personal information, such as the names of US informants. Later, WikiLeaks published the full set of 740,000 documents with no redactions.

The authors of the Pentagon report were also worried about the impact of adverse media publicity accruing from the leak. In particular, they were anxious about media attention on the large number of Iraqi and Afghan civilians who were being injured or killed in the US war effort.

The report said that some of the information contained in Manning’s uploads “could be used by the press or our adversaries to negatively impact support for current operations in the region”.

The release of the redacted final report comes just weeks after Manning, who had served seven years, was allowed out of military prison after Barack Obama cut short her sentence in one of his final acts in the White House. In an interview with ABC News conducted after she walked free, Manning said that the motive behind her massive leak had been a desire to draw public attention to US military actions abroad.

“My intention was to draw attention to this … and do the right thing,” she said.