That's why they told us that the irregular nature of the Al Qaeda threat forced us to circumvent Article I Section 8, requiring Congress to issue declarations of war, and allow the President unlimited power to prosecute the war against terror.
However, the founding fathers were indeed confronted by irregular warfare, and established a response in the Constitution. Chuck Baldwin explains
President Bush should have supported Ron Paul's bill,
H.R. 3076, the September 11 Marque and Reprisal Act of 2001. This is the constitutional way to deal with rogue terrorist organizations. This is the way President Thomas Jefferson responded to the Barbary pirates.
According to Congressman Paul, “A letter of marque and reprisal is a constitutional tool specifically designed to give the President the authority to respond with appropriate force to those non-state actors who wage aggression against the United States while limiting his authority to only those responsible for the atrocities of that day. Such a limited authorization is consistent with the doctrine of just war and the practical aim of keeping Americans safe while minimizing the costs in blood and treasure of waging such an operation.”