"To watch the courageous Afghan freedom fighters battle modern arsenals with simple hand-held weapons is an inspiration to those who love freedom. Their courage teaches us a great lesson-that there are things in this world worth defending. To the Afghan people, I say on behalf of all Americans that we admire your heroism, your devotion to freedom, and your relentless struggle against your oppressors." President Ronald Reagan - March 21, 1983

It's simple enough: every enemy killed in a foreign country increases the number of enemies exponentially. In Afghanistan, the parents, the in-laws, the relatives of the dead, turn against the West. They may not take up arms and they may not join the Taliban, but they will certainly not oppose anybody who wants to kill the men who killed their loved ones. This has always been true - the Canadian columnist George Jonas wrote that communism still survives in those countries which were engaged militarily with the West, including North Korea, Vietnam, Cuba and China.

The military documents revealed by Wikileaks last week illustrate what has been evident for years: Nato has been creating more enemies of the West by the day. Yet Nato soldiers continue to die, and unknown numbers of Afghans die, and the wealth of the West drains away by the billion, making us weaker and more vulnerable.

The most notable successful violence against terrorism on foreign soil is President Reagan's bombing of Libya after Lockerbie, targeting Gaddafi himself. The stealth bombing managed to kill one of Gaddafi's wives, one of his children, and nearly killed Gaddafi. That was a strategy of hitting back and then quickly retreating. Reagan was not going to engage in an ongoing war on foreign soil which was bound to spiral out of control. Reagan learned from Vietnam, President Bush did not, and neither, so it appears, has President Obama.

There was a great deal of outrage and hand-wringing about Reagan's cruel and lawless action, yet it cost less to both sides than the gallons of blood soaked into the earth in Afghanistan on a bad day, let alone in seven years. And today Gaddafi is a business partner of BP.

The most hollow justification for the Afghan war is that unless we fight the terrorists in Afghanistan and other foreign places we will have to fight them at home. But as the convictions of terrorists in Britain demonstrate, it is only at home that terrorists can be fought effectively. No atrocity has succeeded here for quite some time, which is certainly not the case in Afghanistan. And it is difficult to believe that the Government's main concern is to prevent terrorism at home, when it intends to cut the budget of the security services.

Terrorists can be tailed, their phones can be tapped. The security services speak the language, they are familiar with common habits, locations - they know the country better than the terrorists and they have back-up at their disposal. If and when terrorists succeed, their violence gains them only enemies, not converts. What is true of us there, is true of them here.

There is a lot more to be said, and all our leading columnists, Left and Right, have said it. I would just like to add the thought that it was the Soviet Union's defeat in Afghanistan that robbed the Red Army of its terrifying reputation for invincibility and led to the uprisings in the suppressed Soviet Republics and the collapse of the Soviet Union. All a great power has to do to destroy itself is persist in trying to do the impossible.

Afghanistan is an unwinnable war, and our leaders know it