Funny thing, politics. One day the Republican Party is flogging, for $150 a time, pictures of President Bush on the phone on 11 September in a pose they believe shows him to be grave, fully in command and all but invincible; the next day, the former first lady Hillary Clinton is holding up an admittedly wildly exaggerated New York tabloid banner headline blaring "BUSH KNEW". Then all the rancour and politics that have been so suppressed here since 11 September hit the fan, and the mood changed markedly.
So much so, I suspect, that this month could prove to be the turning point in the Bush presidency. It is not so much the revelation that Bush received a CIA briefing at his Texas ranch on 6 August (we do not know whether he actually read that report, but I know what my guess would be) telling him that al-Qaeda may have been planning aircraft hijackings inside the US; it is that the haloes of untouchability and rectitude that Bush and his cronies previously managed to assume so successfully are beginning to slip, day by day. By last Tuesday, for example, we learnt that both the egregious John Ashcroft (Bush's attorney general) and Robert Mueller (the director of the FBI) knew soon after 11 September of an FBI memo of 10 July, warning that al-Qaeda was using US flight schools to train pilots - but that they did not bother to tell the president until recently.
In other words, the finger-pointing has begun in earnest. I have been writing here in recent months of the "internecine warfare" that has been bedevilling Washington - and the ineffectualness of Tom Ridge, the amiable but feckless "director of homeland security" appointed by Bush. Therein lies the nub of all the shenanigans. The CIA doesn't like the National Security Agency, which doesn't like the Immigration and Naturalisation Service, which doesn't like the National Imagery and Mapping Agency, which doesn't like the FBI, which doesn't like the army, which doesn't like the navy, which doesn't like the air force, which doesn't like the CIA, and so on. There is nothing so ferocious as a turf battle in Washington, and these agencies' refusal to co-operate and pool information most likely contributed to the enormous intelligence failure of 11 September. No single mastermind - as Ridge is now meant to be, in lieu of the president - was ever in charge.
The battles will now be fought politically - and it will get very dirty indeed, albeit mostly at a subterranean level. Nobody should underestimate Bush's interest in focus groups and opinion polls and his desperation to be re-elected in 2004. Since the furore erupted over what Bush knew, the administration and the Republicans have moved quickly to seize the moral high ground. They have played the one political winning card they have held so far: flag-waving patriotism. The vice-president, Dick Cheney, speaking in that immensely moralistic tone out of the side of his mouth, was the chosen anointed one to deliver the first magisterial rebuke to the Democrats.
He was at it again the following weekend on television: "I still have a deep sense of anger that anyone would suggest that the president of the United States had advance knowledge that he failed to act upon."
This, clearly, is a dangerous high-wire act of political sophistry for the Republicans. Nobody is suggesting that Bush knew that planes were going to be hijacked and crashed on 11 September, and failed to do anything about it - that is where Cheney's contrived moral indignation is so fallacious and unpleasant - but people do ask whether the president could and should have known that such atrocities were possible and/or imminent. Compare this with the now ritual warning of coming atrocities ("It's not a matter of if, but when . . . we don't know if it's going to be tomorrow or next week or next year") and it is clear that Cheney and the administration are trying to have it both ways. They had no inkling of 11 September, they say, even though intelligence warnings as early as 1994 predicted a suicide plane attack on the CIA and, as late as last August, an FBI field officer warned that Zacarias Moussaoui (the 33-year-old "20th hijacker" arrested and imprisoned in August) was the kind of terrorist likely to fly a plane into the World Trade Center. But if we in Washington are eviscerated by a suitcase nuclear bomb tomorrow, the administration has none the less been sufficiently on top of things to have given us advance warning.
Uncomfortably for the administration, however, it is not just the Democrats who feel that the floodgates have been opened to allow public criticism of Bush and his motley crew. Senator Richard Shelby, Republican vice-chairman of the Senate intelligence committee, now says openly that he and others believe that if intelligence had been acted upon, 11 September might have been averted. Tom Daschle, Democratic majority leader in the Senate, meanwhile says he is "gravely concerned" by recent revelations - not least that the news of Bush's CIA briefing was kept from the public and Congressional leaders like him for more than eight months. (Because of the separation of powers in the US, that is a snub rarely recognised in the UK, where the Prime Minister is an MP: in the US, the president is expected to share intelligence and other security matters with Congressional leaders representing the people.)
The outcome of all this is that the Bush administration and either party in Congress - acutely aware of midterm elections in November - are now watching the polls. Bush's personal rating remains very high, at 75 per cent. But, crucially, the American public is much more equivocal about whether pre-11 September matters could have been handled differently: as many as 31 per cent say the Bush administration did not do enough (compared with 58 per cent who disagree). The chinks in the Bush armour are thus beginning to emerge.
Will his administration now begin to unravel? I wrote last week of the private agony of Colin Powell, stuck in an administration that has systematically humiliated him, but who is staying at his post to show post-11 September solidarity. We now have Ashcroft, privately reviled even by many Republicans, seen to have kept information from the president as well as the director of the FBI. Senator Patrick Leahy, Democratic chairman of the judiciary committee, wants to find out who saw the 6 August intelligence report and when.
The Congressional panel investigating what went wrong on 11 September is now riven with political strife; it has a staff of 23 and a budget of $2.6m, but despite obtaining 150,000 pages of CIA reports, partisan rancour is such that it is at a standstill, unable to make a constructive start to its investigations.
Even the conduct of the war in Afghanistan is being questioned politically, something routinely acceptable in Britain last year, but unthinkable here until now. The veteran Republican congressman from Illinois, Henry Hyde, added a note to his Congressional committee's subvention of $1bn for rebuilding Afghanistan, saying: "We accompany the funds with a rather strong request that the administration give us a plan that is effective." Tom Lantos, a Democratic congressman from California, says that the Bush administration's "failure to act on this important issue may well lead to a failure to win the war on terrorism in Afghanistan".
All of which hardly augurs well for the Bush administration, even though the widely accepted wisdom in Washington - usually wrong, as NS readers know - is that the Democrats lost the first skirmish in this latest furore. Bush is a ruthless man politically, and last Monday flew down to Florida to help his brother retain the governorship there.
"Mr Castro, once, just once, show that you're unafraid of a real election," he shouted to a Cuban-American crowd, rather pathetically trying to echo Ronald Reagan's famous words of the 1980s: "Mr Gorbachev, tear down this wall." But it was the kind of rhetoric needed to solidify the Cuban-American Republican vote, which now preoccupies Bush every bit as much as it did Clinton.
But yet those first chinks in Bush's seemingly impregnable, saintly armour have now been pushed open. Even Republicans are breathing a cathartic sigh of relief that they can now say privately that, after all, they have always considered Bush to be a weak president. And where, people are now muttering, would Bush be without 11 September? He would, to quote a saying of his father's, be in deep political doo-doo.
It is a wretched thing to say, but no less true: whichever side can best, and most subtly, exploit the post-mortems of 11 September will now triumph at the polls in November and in 2004.