The U.S. had said such an act could stir military retaliation. The papers, withheld 25 years, don't seem to bear that out.
" Years ago, Wiener called the case a "rock 'n' roll Watergate," in part because the FBI took an intense interest in Lennon at the time operatives from the Nixon administration perpetrated the Watergate burglary. But on Tuesday, Wiener agreed that given how long the case dragged out, it might more appropriately be characterized as a "rock 'n' roll 'Bleak House,' " referring to the Dickens novel about a years-long inheritance case.
"The release of these final documents, concealed from public view for nearly a quarter of a century, reveals government paranoia at a pathological level and an attempt to shield executive branch abuse of civil liberties under the rubric of national security," said Rosenbaum of the ACLU. "
the article is here
and the files are here