The Taliban guerilla war in Afghanistan and Pakistan is, based on the historical record, not looking good for the guerillas. In the past, guerillas in situations like the Taliban find themselves (hated by most of their countrymen, and losing external sources of support) faced almost certain defeat.
The idea that guerillas are unbeatable was a myth rather firmly established by the Vietnam War, particularly in leftist circles. It is very much a myth. That was known at the time of the Vietnam war. For example, between 1942 and 1965, there were twelve communist inspired guerilla wars. The guerillas won only three of these (China, the first Indochina war and Cuba). The first Indochina war ended in 1954 with the defeat of the French colonial forces. This led to the second Indochina war, which the communists lost. The communist guerillas were defeated when the U.S. left Vietnam in 1970. South Vietnam eventually fell to a conventional invasion by North Vietnam, complete with tanks and artillery. An earlier invasion in 1972 had been defeated, with the help of American air power. But over the next three years, American politicians cut off all military aid to South Korea, while Russia and China built up the North Vietnamese armed forces.
So the belief in the early 60s that the Viet Cong could be beaten was not a fantasy. But to defeat them certain realities had to be addressed. Of course the important thing was not that the guerrilla could be beaten, but rather that each war was a unique case. There was no formula that the insurgents could apply to insure success, nor one that their opponents could apply to insure their success. The conduct of unconventional warfare depended upon such things as objectives, leadership, organization, discipline, culture, foreign support, and a myriad of other factors, any or all of which could be different depending upon the country. To win as a guerrilla or to beat the guerrilla one had to tailor ones activities to the particular situation.
Just as the U.S. had failed to study the lessons of its own experiences with insurgency, so too it failed to do more than take superficial notice of the details of those situations where guerrillas had been defeated. American political and military strategists failed to take notice of the differences among the many insurgencies that had been defeated and Vietnam, and therein lay their most grievous failing.
But in the last decade, the U.S. military has rediscovered the lessons of history. Actually, this began in the 1970s, when the U.S. Army introduced the mandatory, and serious, study of military history. The officers who began their careers back then, are now running the army. While many media pundits see the Taliban as unbeatable, the army officers know better.
The most common cause of guerilla defeat is the lack of external support. The Taliban had support from fellow Pushtuns in Pakistan, until recently. But now the Pakistani Army is clearing out one Taliban stronghold after another. So serious are the Pakistanis, that they just moved 100,000 troops from the Indian border and into the tribal territories. This doubled the number of troops there, even as the Taliban have lost half their combat strength in the last six months. Pakistani Taliban are now fleeing into Afghanistan for refuge.
But there is no joy for the Taliban in Afghanistan either. While the Afghan Taliban have considerable support from the drug gangs (which use the Taliban as muscle to protect the production and smuggling of opium and heroin), NATO troops are making a major effort to shut down the drug operations. This is enormously popular worldwide, and especially inside Afghanistan and neighboring countries. That because the local nations, despite their poverty, find themselves with millions of drug (usually the cheaper opium) addicts. While the drug gangs bribe many local officials and security forces, the majority of the population is firmly against the drug operations.
Even among their core supporters in Helmand province, and around Kandahar, the Taliban are losing support. This region was always the heartland of Taliban support (the original Taliban came from the Pushtun tribes in this area), but the Taliban have been having a harder time recruiting fighters from these Pushtun tribes because, despite the high pay (several times what an Afghan policeman or soldier makes), Taliban tactics get these guys killed too easily. A current example can be seen in the battle for Marjah, where the Taliban leadership got out, and left behind local hires, with promises that they would be able to get out after killing some foreign troops. Hasnt been working out that way. While the Taliban will pay the families of these dead gunmen, other potential recruits will not be encouraged by this generosity. Getting revenge for their dead kinsmen is a bigger draw, but since the Taliban gunmen were killed by anonymous foreign troops, most Afghans are content to simmer, and not court certain death for the sake of family honor. Not now anyway, maybe later.
Besides, there are more immediate revenge issues, as the majority of Afghans (the Tadjiks, Uzbeks, Hazaras and so on), are still seeking vengeance from the Taliban for past murders. The biggest problem for the Taliban is not foreign troops, but angry and vengeful Afghans. The Taliban leadership have no strategy for this, other than establishing another Taliban dictatorship in Afghanistan.
The Taliban leadership are true believers, or tribal politicians eager to find some opportunities to increase their power. Many of the hustlers in the Taliban leadership are either becoming strictly drug lords, or switching allegiance to the government. That's another problem with Afghanistan. There's never been a real national government, and there's always been a lot of corruption in the tribal governments that have ruled the area for thousands of years. But at least the tribal leaders would pass the loot around. The current effort to create and sustain a real national government is crippled by the corruption. But the Taliban rule of the late 1990s was also corrupt, and not even as successful as the current gang of thieves and wannabe bureaucrats. There are no easy solutions, or victories, in Afghanistan.