I added the bold because I think the statement needs to be evaluated. Defeat is an interesting word, true defeat for Israel means no more Israel, but Global Scout states defeat in the campaign, a much more microcosmic defeat. One that could sow the seeds of true defeat if Israel isn't careful.
Again I will argue those who are blinded by the conventional doctrines of war, where victory/defeat is focused almost totally on red and blue forces, instead of the larger strategic picture. One does not need to destroy a nation's armed forces then occupy to defeat it. If an irregular force can coerce/manipulate another nation to behave a way to its liking, then the irregular force wins.

One could argue that irregular forces defeated Spain because the Madrid bombings resulted in a change of government and Spain withdrawing from Iraq. The same is happening Poland now, due to irregular attacks against Polish forces and their Ambassador in Iraq, and soon they will depart.

S. Vietnam could be argued for days, but I think most of us will agree that the focus of the Viet Cong and NVA was not defeating our military, but rather conveying to the U.S. population that they couldn't be defeated, among other things.

Lenin overthrew the Russian government with irregulars? How? He moblized the population, just as Mao did some 20 plus years later.

It is great that our western militaries can't be defeated by irregulars, but the fact remains is despite our might, the irregulars can still manipulate the superpowers.

Here are some questions in regard to Israel's escapade into Lebanon:

1. Do the people in Lebanon support the Hezbollah more or less after the conflict? The fact is it was the Hezbollah who are seen as the heros of the conflict, and even those who didn't support the Hezbollah previously tended to favor them after Israel started destroying Beirut's infrastruture.

2. Who became more isolated in the international community, Hezbollah or Israel? While most the international community will never support Hezbollah, they effectively provoked Israel to take actions that further isolated them internationally, which limits their ability to undertake similiar actions in the future.

Irregular warfare is not about defeating your adversary's military force, that is checkers. It is an attempt to asymmetrically corner him and force him to change his behavior, this is called chess.

Winning and losing can be defined many ways. Ultimately there are forces that would like to see Israel go away, that would be probably be a total victory for them, and I agree I don't think that is feasible in one fatal swoop, but over time Israel can be degraded by these activities, and so can we, Europe and other nations. The answer is not to simply send our military forces in to crush them unless we're willing to break international law and wage total war on a population.

The answer remains elusive, if it was simple we would have implemented it already.