The Algerian government and Hafez both faced a credible Islamist threat, whose atrocities rallied support for the regime.
Today, in Iraq, we see a threat whose outlines are far more clearly defined and whose consequences could be far more deadly.
The Lebanese are the faraway other, and also the hosts of the Hizbullah threat, whose attacks on Israel they have done nothing to prevent.
Before then Iraq was considered essentially a regional threat whose conventional military power was far weaker than it was during the 1991 gulf war.
In March 2007, a year before mortgage bets felled Bear Stearns, Mr. Whalen said at a conference in Washington that subprime home loans posed a threat whose scope was "almost unknowable".
The Clinton administration has tried to balance sensitivity to Russia's concerns with mounting pressure to do something about a missile threat whose rapid expansion has tended to vindicate the hawks.
The tough measures taken at Manchester and other British airports have also been prompted by Britain's long struggle with terrorism, a threat whose full force the United States discovered only last week.
This time the casus belli is murkier, resting not on the harboring of mass murderers but on the novel (for America) doctrine of pre-emption, and on a threat whose urgency may be unknowable.
But the entire public health system needs to be bolstered to create a safety net strong enough to protect the nation from a threat whose dimensions are difficult to anticipate.
