“Today,” says Matthew Yglesias, “as a swirling financial panic pushes national security issues out of the headlines it’s worth returning to bin Laden’s warning.”
Osama bin Laden himself in his November 2004 pre-election message. In that tape, bin Laden described a strategy of “bleeding America to the point of bankruptcy” by provoking us into undertaking costly military adventures. 
Mocking a certain panicky quality in American policymaking, bin Laden bragged that “all that we have to do is to send two Mujadedin to the farthest point East to raise a piece of cloth on which is written al-Qaeda in order to make the generals race there to cause America to suffer human economic and political losses without their achieving for it anything of note other than some benefits to their private companies.”
…the $100 billion or so per year we’ve been spending on [Iraq] has cost us dearly.
The view from Cato Institute in 2005 reveals Bush is wrong to “claim that Iraq is the central front in the war on terrorism”.
“The truth is that ridding the world of Saddam Hussein’s brutal regime did not eliminate an Al Qaeda sanctuary or a primary source of support for the terrorist group.
A Thinking Policy:
“The military’s role in the war on terrorism will mainly involve special operations forces in discrete missions against specific targets, not conventional warfare aimed at overthrowing entire regimes. The rest of the war aimed at dismantling and degrading the Al Qaeda terrorist network will require unprecedented international intelligence and law enforcement cooperation, not expensive new planes, helicopters, and warships.
“Therefore, an increasingly large defense budget is not necessary to fight the war on terrorism. Nor is it necessary to protect America from traditional nation-state military threats—the United States is in a unique geostrategic position; it has no military rivals and is relatively secure from conventional military attack because of vast oceans on its flanks and friendly neighbors to the north and south.
“In fact, U.S. security would be better served by adopting a less interventionist policy abroad and pulling back from the Cold War–era extended security perimeter, which necessitates forward-deployed military forces around the world.
“If the United States adopted a balancer-of-last-resort strategy (allowing other countries to manage the security of their own regions), most overseas U.S. military deployments could be eliminated and the defense budget could be substantially reduced.”