William Hague's quick trip to Washington on Friday was timely indeed. Just after assuming office, the new Foreign Secretary had stressed that "it is our most urgent priority? to make sure we get a grip on what is going on in Afghanistan". Arriving right on the heels of the Afghan President Hamid Karzai, Mr Hague came at a critical moment for planning both political and military aspects of the long war against the Taleban and al-Qaeda.

While there was much for Mr Hague and Hillary Clinton, the US Secretary of State, to discuss, particularly the menace of Iran's nuclear weapons program, Afghanistan and the closely intertwined issue of Pakistan (hence "AfPak") reportedly predominated. This was entirely appropriate given the critical decisions Nato faces in the year ahead.

Failure in Afghanistan, bad enough, would dramatically increase the chances of destabilising Pakistan--and its substantial nuclear arsenal falling into the hands of Taleban or other extremists. Moreover, Nato itself is at risk in Afghanistan, as complaints mount in Canada and America that some European allies are not pulling their fair share of difficult combat missions. These disputes threaten to poison its first out-of-area operation, perhaps the alliance itself.

Nato's central challenge is not so much the current Afghan military situation as to avoid losing its will and staying power. As with the global war on terror generally, this war will be protracted, to which Nato must either be steeled or, sooner or later, face inevitable negative consequences.

The most grievous problem is the self-inflicted wound that President Obama administered: his vow to begin withdrawing in summer, 2011. This pledge, heard and well understood by Taleban, undoubtedly reflected Mr Obama's own ambivalence about the Afghan war, as well as the Democratic Party's deep-seated weakness on national security.

Unfortunately, another key problem is that both the Obama Administration and the new British Government have misdefined the objective. General Stanley McChrystal recently said, for example, that while the Taleban's momentum had been stopped, winning depended on the Afghan people having faith in their future. Mr Hague said something quite similar about Britain's objective: "For Afghans to be able to provide for their own security and livelihood without presenting a danger to the rest of the world."

Faith in the future and security are certainly benefits of Nato's military campaign, but our objective is not to remake Afghanistan. That is the Afghans' job. If Kabul eliminated corruption, conducted free and fair elections, and greatly increased its military reliability and capabilities, that would help to eliminate the Taleban.

But we cannot withdraw from the conflict just because the Afghans may not be meeting our standards. Leaving due to Afghan government failures, of which there are and will be many, would jeopardise our strategic objectives, frustrating the very reasons for intervening after 9/11 in the first place: preventing terrorists from re-establishing Afghanistan as a base, or using it to destabilise Pakistan and seize control of Islamabad's nuclear weapons.

We must achieve these objectives--which means essentially destroying the Taleban--whether or not the Afghan government shapes up. That is the right metric, not nation building. This is a hard truth, but realistic unless you are prepared to risk a nuclear Taleban.

With Pakistan, Britain could play a critical role. As Mr Hague said last year, "the multiplicity of British connections to Pakistan, through hundreds of thousands of families as well as Pakistan's leaders, gives Britain a particular role in supporting Pakistan's democratic future". While animosity to American pressure can be a powerful force among some Pakistanis, it may be that Britain's long-standing relations can smooth out difficulties. Of course, given continuing resentment about London's imperial past, its intervention is not a panacea. But what would be useful is a better combination of British and American influence, advancing our common agenda with Pakistan, tactically deciding which country takes the political or military lead on which issue. This will produce a stronger result than the two countries acting alone.

And how will the Liberal Democrats react to a more forward-leaning British position on AfPak? This could be one of the coalition's first major tests, and the outcome is anyone's guess. Moreover, David Cameron's new National Security Council is also on trial. One potentially important bureaucratic point is that the National Security Council will be administered by a senior careerist in the Foreign and Commonwealth Office, rather than by an advisor reporting directly to the Prime Minister. Where bureaucrats sit often determines where they stand, and turf battles among ministries are as intense in London as in Washington. This new structure may prove inadequate in resolving inter-agency disputes, and actually impair decision making.

Terrorism and nuclear proliferation remain the predominant threats of our time, and AfPak is one of the primary arenas of conflict. The UK, the US and the West as a whole have an enormous stake in victory over the Taleban. Now, hard decisions lie ahead, far removed from the domestic issues familiar to Mr Cameron. We know already in America that voters will not tolerate failure, and we may soon see whether the mood in Britain is the same.

John R. Bolton is a senior fellow at AEI.

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