War as the only Choice?

Irfan A. Khawaja on HNN says that the leftist approach to the Al-Quaeda problem is no solution, but a joke in his lengthy essay on Abramsky piece on Open Democracy.
He is right that the Leftists approach is born from an illusion and certainly not the right way to change anything, but need there be much change?

I especially critizise the following paragraph:

But the answers on that score are crystal-clear. If someone declares war against you, it makes perfect sense to declare war against them. If you declare war against someone, it is imperative to do what it takes to defeat them: i.e., either subjugate them or destroy them. That is what we have to do to Al Qaeda. And sorry to burst any bubbles, but the two major battlefields are Iraq and Afghanistan. Either we defeat Al Qaeda & Co. in both places or we lose the war altogether.

This is true when it comes to the classical sense of war, f.e. a war between Britain and the United States. But in this context, the war between the western civilisation and Al-Quaeda doesn't fit. Instead, we have a far more difficult situation of guerilla warfare by a terrorist cell that is much bigger than any other before. Instead of pure military means, we have to employ new devices to beat terrorism. This is not a military battle, but a cultural battle and not warzones but wealth will decide it.
On every terrorist in the middle east come at least a thousand non-militarists in every muslim country. We couldn't beat the IRA or the ETA with military means, why should it be different with another religious fanatics group, like the Al-Quaeda.
If Mr. Khawaja is right on this war, then we would have had an IRAQ full of Al-Quaeda before the war or at least some training camps. However, it was truly devoid of any muslim terrorists, but instead filled with liberty resistance groups that tried to topple the dictatorship of Mr. Saddam Hussein.

Afghanistan is a different terrain because of one reason: Al-Quaeda was there before 9/11 and has staged attacks from this cell. It was a rightfull approach to destroy the Taliban regime and erradicate the Al-Quaeda training grounds, which hasn't happened at all as we see today.
This reason justified the war in my eyes, because it was a reaction to a direct threat instead of a hypothetic one by Saddam. The war against Iraq was not a direct step in the war against terror, but a private action against the gruesome dictator Saddam Hussein. The USA could have attacked North Korea with the same reasons, but they chose to take on Saddam.
When all is said and done, we had a defensive war in Afghanistan and an aggressive act in Iraq and this truly distinguishes both of them.

Even the reference to WW II is no help, because the Pacific island hopping was the result of an active act of war from the Japanese and the Normandie-landing was a reaction to Hitler's continuous attacks on US assets in the North Atlantic. So, Iraq doesn't qualify due to either of these scenarios.