Another Terror Threat, Or Much Ado About Nothing ?

Once again, Brian Ross at ABC News is breathlessly reporting a grave threat to the Republic:

Senior U.S. intelligence officials tell ABC News new intelligence suggests a small al Qaeda cell is on its way to the United States, or may already be here.

The White House has convened an urgent multi-agency meeting for Thursday afternoon to deal with the new threat.

Top intelligence and law enforcement officials have been told to assemble in the Situation Room to report on:

–what steps can be taken to minimize or counter the threat,

–and what steps are being taken to harden security for government buildings and personnel.

“It suggests they have information that the cell or cells coming this direction want to attack a government facility,” Brad Garrett, a former FBI agent and ABC News consultant, said.

Law enforcement officials say the recent failed attacks in London have provided important new clues about possible tactics.

And officials say the London attackers use of the Internet left important clues that are being used to decode other e-mails that had initially been deemed unimportant but are now taking on new significance.

A senior administration official said the level of concern of a new terror attack is now higher than it has been in some time, and the meeting this week in the situation room is one of a number that have been convened in light of the new intelligence and what happened in London.

A couple points.

First, as Brendan Loy asks, if this is such a grave threat, why is the White House waiting until Thursday to talk about it ?

Second, how is this “latest” terror threat any different from the numerous false alarms we’ve seen reported in the media since September 11th ?

Finally, can someone please tell me that our intelligence agencies can tell the difference between false alarms and real threats ?