A combination of the intensification of the debate about "who knew what and when?" and generalised warnings about future attacks has made the US perhaps more jittery than it has been since just after September 11th.
The nerviness took its toll on share values yesterday as investors protected themselves ahead of the Memorial Day holiday weekend, but the markets recovered later.
Yesterday the Brooklyn bridge in New York was closed for an hour and police presence in the city was stepped up following an unspecific warning both to the bridge and the Statue of Liberty.
A parcel on the bridge was found by bomb squad officers to be harmless. The FBI said the information was based on interviews with captured al-Qaeda and Taliban members detained in Cuba. Describing the information as "general threats to New York City", Police Commissioner Raymond Kelly said his department was "taking all necessary precautions".
At national level, the generalised warnings continued to flow.
The Defence Secretary, Mr Donald Rumsfeld, said terrorists inevitably would acquire weapons of mass destruction from countries such as Iraq, Iran or North Korea. The Secretary of State, Mr Colin Powell, launching his department's annual report on terrorism trends, cautioned on Tuesday that "terrorists are trying every way they can" to get nuclear, chemical or biological weapons. The White House, however, said it was not raising the nationwide terrorism alert status because intelligence was too vague.
In an interview with Italy's RAI television, President Bush echoed the general warnings given by administration officials in recent days. "The al-Qaeda still exist, they still hate America and any other country which loves freedom and they want to hurt us," Mr Bush said. "They're nothing but a bunch of cold-blooded killers."
The president's spokesman, Mr Ari Fleischer, has spoken of "a recent increase in the level of chatter" in intelligence intercepts, precisely the sort of increase which also preceded September 11th.
There is some scepticism in Washington that some of the increased chatter from security and political sources about potential threats is, at least in part, a cynical forestalling of the sort of criticism which is now being raised about the pre-September 11th state of alertness. Its lack of specificity, however, makes it virtually useless to the general public.
New York Times columnist Thomas Friedman put such doubts bluntly in a piece yesterday. "Ah, excuse me, but could we all just calm down here?" he asks. "What are we supposed to do with such information? Never go into another apartment building because reports suggest an al-Qaeda cell may rent an apartment just to blow it up? Don't go outside? Pat the belly of every pregnant woman to see if she is a suicide bomber?"
The vigilance must continue but this is the sort of fight you can never win definitively, Friedman argues. He, for one, intends to enjoy his Memorial Day weekend.
"If the FBI director wants to interrupt my weekend with a specific warning, I'll be all ears; otherwise pipe down and chill out. Remember it's supposed to be al-Qaeda that's running scared, not us."
