Four and a half years after the fall of the Taliban, Afghanistan is still highly unstable. And it seems to be getting worse rather than better. Every few days now, the resurgent Taliban carry out another deadly attack on school children, aid workers, or local or international security forces. It is a grim return on the outside world's huge investment in Afghanistan. Yet while the international community has done an enormous amount to help the country recover from its failed-state condition, it has resisted tackling the problem at its very root -- Islamabad. Truth is, Afghanistan will never be stable unless Pakistan's military government is replaced with a democracy.

Pakistan's primary export to Afghanistan today is instability. On the most basic level, attacks in Afghanistan , including suicide bombings, are often planned and prepared at Taliban training camps across the border. Islamabad claims to be doing all it can to stop this infiltration. But President Pervez Musharraf's protests ring hollow when he has done so little to address the concerns raised by his Afghan counterpart Hamid Karzai, that Taliban leaders are operating out of sanctuaries in Pakistan.

One needs only to look at the military's close relations with religious radicals to understand how unreliable a partner it is in stabilizing Afghanistan. Militant Islamist groups that Mr. Musharraf banned under the international spotlight following 9/11 and the 7/7 London bombings still operate freely. Jihadi organizations have been allowed to dominate relief efforts in the aftermath of the October 2005 earthquake. The military has repeatedly rigged elections, including the 2002 polls, to benefit the religious parties over their moderate, democratic alternatives.

In short, Pakistan is ruled by a military dictatorship in cahoots with violent Islamist extremists. The military has no interest in democracy at home, so why does the outside world expect it to help build democracy next door?

If we are really going to get to the core of Afghanistan 's instability, therefore, we must tackle Pakistan. Above all, this means returning the country to democratic rule. After seven years under the military, this is not an easy task, but some institutions are still surviving -- just. The judiciary, for example, has been badly degraded under Mr. Musharraf and his army colleagues; but there is enough left to give hope for some kind of gradual resuscitation.

Moderate political parties are also struggling to hang on; down but not yet out, they could recover relatively quickly if given a democratic chance. Pro-dictatorship voices regularly argue that those parties were highly corrupt and that it was their corruption that justified the 1999 coup that brought Gen. Musharraf to power. But they refuse to condemn or even acknowledge the military's large-scale, institutionalized corruption.

So much has been grabbed by the military that it will take years just to catalog it. The military has acquired vast tracts of state-owned land at nominal rates; its leaders dominate businesses and industries, ranging from banking to cereal factories. Their control of the economy has grown so great it will present an enormous challenge to any future democratically elected government.

That civilian government, when it comes, will also be moderate in character and far more inclined to tackle, in earnest, the scourge of Islamic radicalism. Even in the rigged 2002 election, the religious parties polled only 11% of the vote. A fully free and fair race will squeeze out radical forces that have thrived under military rule and which play havoc with Pakistan's weak neighbor to the northwest. In addition, unlike the military, which always thrives in a hostile environment, a civilian government will have a stronger interest in peace with India. And who wouldn't sleep safer knowing that Pakistan 's nuclear bomb was in democratic hands?

Democratic governance would also bring a much-needed opportunity to overhaul the country's education system. As the state system has consistently failed young people for decades, madrassas have taken up the slack, with the most extreme religious schools helping to radicalize tens of thousands of Pakistanis -- and Afghans -- filling heads with intolerant visions of Islam, far from the mainstream of South Asian Muslim society. The country needs a properly funded, state-run, secular education system.

Bringing all this about is an enormous task, but demilitarizing and deradicalizing Pakistan is truly the key to bringing about stability in Afghanistan and the wider region. Governments now working so hard to support Afghanistan will only be spinning their wheels until they make Pakistan a top priority and apply maximum pressure on Islamabad to ensure the 2007 elections are actually free and fair, by applying clearly defined benchmarks and insisting on competent international observers. As long as the military and the madrassas rule just across the border, Afghanistan will never find peace.

Lord Patten, former EU commissioner for external relations, is chairman of the International Crisis Group and chancellor of Oxford University.