One of the best moments in one of my favourite shows is when Bernard Woolley, Jim Hacker's principal private secretary in Yes, Prime Minister, muses on the eternal problem of government leaks.
"That's another of those irregular verbs, isn't it," he says to the PM. "I give confidential briefings, you leak, he is being prosecuted under Section 2a of the Official Secrets Act." The United States doesn't have an Official Secrets Act, of course. But in every other respect Bernard's joke is playing out in Washington in deadly earnest.
The Bush administration's obsession with preventing leaks, and generally running a tight ship, long predates 9/11. Witness such avatars of openness as Dick Cheney, and his successful fight to keep the doings of the special energy committee, chaired by the Vice-President, out of the public domain. But the terrorist attacks have turned obsession into paranoia, and provide the classic wartime pretext - loose talk cost lives - for today's clampdown.
Over at the CIA, the director, Porter Goss, has taken the virtually unprecedented step of publicly sacking Mary McCarthy, a senior official, for the unauthorised disclosure of classified information - though it remains a mystery precisely what. Or take the pair of lobbyists for the pro-Israel AIPAC lobby who received some inside info from a friend at the Pentagon, which they then passed on, surprise, surprise, to the Israeli Embassy.
The Pentagon official has been jailed for 12 years, while the lobbyists are being prosecuted - not for passing secrets to a foreign power, ie Israel, but for passing them to reporters. If the government wins, in theory, any officials and journalists who enjoy a good gossip could be committing a crime.
But it gets creepier still. The National Archives, the equivalent of our Public Records Office, have secretly reclassified more than 50,000 documents at the behest of the Bush administration - some of them previously available to historians for a generation. And spookiest of all, the FBI wants the return of all classified documents in the files of the famous muckraking journalist Jack Anderson, who died last December.
True, there's some history here. The FBI was a constant target of Anderson, prompting its legendary director J Edgar Hoover to describe the reporter as "lower than the regurgitated filth of vultures". His children say they will go to prison if necessary rather than hand over their father's papers, most of which go back at least 20 years.
But shouldn't death get the government, as well as the taxman, off your back? In a sense you can't blame the administration. The past six months have seen a couple of blockbuster leaks: the New York Times scoop about the warrantless domestic wire-tapping by the ultra-secret National Security Agency; and the secret camps for terrorist suspects in Eastern Europe operated by the CIA, revealed by the Washington Post.
Ms McCarthy, the government suggested, was the source of the latter. Her lawyer flatly denies this. So what did she divulge, and to whom? It really doesn't matter. She violated the US equivalent of the Official Secrets Act, and paid the price. Which brings us back to Bernard's irregular verb.
Ever since the invasion of Iraq was a gleam in Dubya's eye, his administration has been leaking like crazy - mostly deliberate lies, as in the claims about Saddam's alleged weapons of mass destruction put about by "senior US officials", that decorated the front pages daily before invasion.
But these are of the variety passed out at one of Bernard's "confidential briefings". These leaks don't count. Nor, apparently, does the fact that after it became obvious that Iraq had no WMD, Bush himself authorised the passing of classified pre-war US intelligence to reporters about the great threat posed by Saddam. There was much tut-tutting, but general agreement that if Bush can't authorise such disclosures (which could get any other official sent to prison), then who can? Meanwhile, a long, hot summer looms, of reporters hauled before grand juries as prosecutors try to force them to divulge sources for the CIA camps and wiretapping revelations.
But take heart; some "confidential briefings" can backfire. The illegal disclosure of the name of CIA operative Valerie Plame, in which the White House was involved, has already brought down Lewis Libby, Cheney's once-mighty chief of staff. On Wednesday Karl Rove, Bush's closest aide, was back before the Plame grand jury for the fifth time, amid renewed speculation that he may yet be indicted along with Libby.
If so, it would prove that there is some justice. It would also underline the immortal observation of the devious Sir Humphrey in Yes, Prime Minister: "The ship of state, Bernard, is the only ship that leaks from the top."