For some 20 years, in another and more youthful phase of my life, I was one of the (apparently) several hundred thousand Americans who possessed a “top secret” security classification.

This was deposited upon me I know not why, as I was a Korean War non-commissioned officer, my sole military qualification that of “small-unit infantry leader,” on my way to the Far East Command. You may imagine how many secrets I knew! Some kind of foul-up further up the line I supposed.

My clearance stayed with me throughout my military service during the Korean War, through an active Army Reserve commitment and through a period of involvement in Cold War political warfare undertakings meant to provide Western intellectual and cultural publications and art to readers inside the Soviet bloc and in the Middle East and Asia. It even lasted through my encounter with a think tank dealing with international relations and strategy, and with why the Vietnam War was a disaster. My top secret clearance went on and on.

It was not a card in my wallet, or a subscription to be renewed, nor did it weigh on my mind. I kept it even after a Soviet KGB man at the U.N. struck up a conversation with me at a party in New York City, and two sober-meined (and obviously well-informed) FBI agents subsequently invited me out for a coffee and asked if I wouldn’t like to pursue the acquaintance on their behalf. I said that if the Russian called me, I would let them know. But I wouldn’t pursue him in order to set him up, which is what they had in mind. They seemed to find this a reasonable moral distinction to draw, thanked me and paid for the coffee.

When I left the hushed halls of secrecy for freelance writing, nobody wrote to expel me from the “cleared” world. For all I know, even now, three American wars and six American presidencies further on, including the Obama administration, for which I voted (now operating its pitiless inquisition into whistle-blowers, with life-imprisonment for them all — “Off with their heads!”), I may still be possessor of a TS clearance. Some kind of foul-up further up the line.

Now the reason I am writing all of this, at the risk of lifetime incarceration in a Marine Corps brig or a Moscow airport men’s room, is that never in my life have I known a top secret!

Even the non-top secrets I have ever known were secret only because the U.S. government would have been politically embarrassed were they known to the American public or to Congress. They were already long known to the Soviet Union and the Warsaw Pact bloc, who were America’s then-enemies.

Take the operation for sending dissident Marxist literature and avant-garde American and European art and literature to the Soviet bloc. The people who received this material in the mail or had it distributed to them by other means were not such fools as not to know — and be grateful — that Western agencies were sending it.

The people from whom the operation was kept secret were Congress and the American public. Why? Because they might be (and some powerful individuals certainly would have been!) outraged that Marxist writings, dissident or otherwise, and “decadent,” abstract or avant-garde Western art, was being distributed abroad by the American government at taxpayer expense.

The secret that during the Cold War the CIA sponsored the activities, conferences and magazines of the liberal-internationalist and anti-Comintern Congress for Cultural Freedom is even today cited with outrage, not only by right-wing figures in the West but by most of the Western liberal-intellectual world. The reputations of the poet Stephen Spender and the New York intellectuals Irving Kristol and Melvin Lasky (the latter founder and inspiration of the Congress’s Encounter magazine) were permanently tainted by their creation of probably the most important and influential international intellectual magazine of the 1953-1991 period.

The principal “outrage” for which Bradley Manning is today imprisoned is the video he revealed to the online world of an American helicopter in Iraq pitilessly shooting up a group of civilians, including would-be rescuers and children. To whom was this video a revelation? Not, surely, the Iraqis who were victims of this barbarous act, and had seen it often replicated. It was being kept a secret from the American public.

What crime is Edward Snowden accused of committing? Not his revelation of American global eavesdropping on foreign governments, which every major government in the world already knew of, or took for granted as existing. Snowden is an international political fugitive because he revealed to the American people what their own government was doing.

Big Brother exists! But he is an American. This is the big secret which the Obama administration spends billions of dollars and enlists millions of individuals to conceal from the very people who are paying for it all. If, or when, this is grasped, Americans will truly have a right to be horrified — assuming it is not too late.

Visit William Pfaff’s website for more on his latest book, “The Irony of Manifest Destiny: The Tragedy of America’s Foreign Policy” (Walker & Co., $25), at www.williampfaff.com.