WASHINGTON—The Justice Department’s World War II effort to punish Chicago Tribune journalists for disclosing naval intelligence was known in 1942.

But the legal analysis behind it, as reported by The Wall Street Journal Wednesday, remained secret until last month, when the Obama administration released a selection of historic opinions dating from the 1930s to the 1970s prepared by the Office of Legal Counsel and its predecessors.

“For us, this volume was truly a labor of love and respect for the history, traditions, and people of this Office and the Department of Justice,” Assistant Attorney General Virginia Seitz and staff attorney Nathan Forrester, who edited the selection, write in the foreword....