CNN correspondent Arwa Damon found the seven-page journal in the ruins of the consulate in Benghazi. Since then, the State Department has called the network "disgusting" for using the journal in its reporting; the network has defended itself; and other journalists have weighed in on the lack of security surrounding the Libyan compound. The controversy has also popped up repeatedly on Fox News.
Cooper, who was the first to mention the existence of the journal last Friday after The Huffington Post and other outlets questioned CNN about it, used his "Keeping Them Honest" segment to push back.
"'360' and CNN have become part of the story and that is the last place I or anyone in this profession ever want to be," he said. He then tackled the State Department, which has accused CNN of removing evidence from a crime scene and of violating its pledges to Stevens' family.
"Now, no one likes to be called disgusting, particularly by a spokesperson for the United States State Department," Cooper said. "But we do invite you and them to hold us to the same standards that we hold others and try every night to meet ourselves."
He said CNN had not quoted from the journal "out of respect" for Stevens' family, and denied the State Department charge that quotes had been emailed between colleagues.
He said the journal was "significant" because it complicated the official White House line at the time -- that the attack was part of the broader global protests against an anti-Muslim film, rather than a pre-planned effort.
"CNN did not publicly announce we'd found it out of respect for the family," he went on. "Instead, as CNN does with every story, our correspondents and our producers sought as many other sources as we could find and in fact we found three other sources, including one who had a detailed conversation with the ambassador which confirmed much of what we felt important in the journal."
Cooper then defended CNN's use of the journal in reporting.
"It's our job to inform you of information that's important," he said. "This was not broadcasting gossip from the pages of someone's diary. This was not reporting salacious details of someone's private life. This was reporting information that could impact the national security of the United States and the safety of U.S. installations in other countries."