Looking back on his tenure, Hagel said in the Dec. 10 interview that he remains puzzled as to why some administration officials sought to “destroy” him personally in his final days in office, castigating him in anonymous comments to newspapers even after he had handed in his resignation.

Although he does not identify her by name, Hagel’s criticisms are clearly aimed at Obama’s national security advisor, Susan Rice, and some of her staff. Hagel’s former aides, and former White House officials, say the defense secretary frequently butted heads with Rice over Syria policy and the U.S. military prison at Guantánamo.

The former Pentagon chief offers a view from inside an administration that was caught flat-footed by the multi-sided conflict in Syria and by the subsequent onslaught of the Islamic State. His account describes an administration that lacked a clear strategy on Syria during his time in office and suggests that it may not have one anytime soon — despite the mounting carnage and waves of refugees.