Last week, I found myself at yet another think tank-type meeting about Afghan policy choices. Toward the end, one of the participants, who had long experience in government, asked a deceptively simple question: What would happen if we failed?

First, the question requires a definition of failure. As I’ve argued, in my view, a purpose of American policy in Afghanistan ought to be to prevent a second coercive Taliban revolution in that country, not only because it would bring misery to Afghans (and, not incidentally, Afghan women) but because it would jeopardize American interests, such as our security against Al Qaeda’s ambitions and our (understandable) desire to see nuclear-armed Pakistan free itself from the threat of revolutionary Islamist insurgents. So, then, a definition of failure would be a redux of Taliban revolution in Afghanistan—a revolution that took control of traditional Taliban strongholds such as Kandahar and Khost, and that perhaps succeeded in Kabul as well. Such an outcome is conceivable if the Obama Administration does not discover the will and intelligence to craft a successful political-military strategy to prevent the Afghan Taliban from achieving its announced goals, which essentially involve the restoration of the Afghan state they presided over during the nineteen-nineties, which was formally known as the Islamic Emirate of Afghanistan.

What would be the consequences of a second Islamic Emirate? My scenarios here are intended analytically, as a first-draft straw-man forecast:

The Nineties Afghan Civil War on Steroids: Even if the international community gave up on Afghanistan and withdrew, as it did from Somalia during the early nineties, it is inconceivable that the Taliban could triumph in the country completely and provide a regime (however perverse) of stability. About half of Afghanistan’s population is Pashtun, from which the Taliban draw their strength. Much of the country’s non-Pashtun population ardently opposes the Taliban. In the humiliating circumstances that would attend American failure, those in the West who now promote “counterterrorism,” “realist,” and “cost-effective” strategies in the region would probably endorse, in effect, a nineties redux—which would amount to a prescription for more Afghan civil war. A rump “legitimate” Afghan government dominated by ethnic Tajiks and Uzbeks would find arms and money from India, Iran, and perhaps Russia, Europe and the United States. This would likely produce a long-running civil war between northern, Tajik-dominated ethnic militias and the Pashtun-dominated Taliban. Tens of thousands of Afghans would likely perish in this conflict and from the pervasive poverty it would produce; many more Afghans would return as refugees to Pakistan, contributing to that country’s instability.

Momentum for a Taliban Revolution in Pakistan: If the Quetta Shura (Mullah Omar’s outfit, the former Islamic Emirate of Afghanistan, now in exile in Pakistan) regained power in Kandahar or Kabul, it would undoubtedly interpret its triumph as a ticket to further ambition in Pakistan. Al Qaeda’s leaders, if they survived American drone attacks, would encourage this narrative and support it as best they could. The Pakistani Taliban would likely be energized, armed and financed by the Afghan Taliban as they pursued their own revolutionary ambitions in Islamabad. In response, the international community would undoubtedly fall back in defense of the Pakistani constitutional state, such as it is. However, the West would find the Pakistan Army and its allies in Riyadh and perhaps even Beijing even more skeptical than they are now about the American-led agenda. In this scenario, as in the past, Pakistan’s generals would be tempted to negotiate an accommodation with the Taliban, Afghan and Pakistani alike, to the greatest possible extent, in defiance of Washington’s preferences. The net result might well be an increase in Islamist influence over the Pakistani nuclear arsenal, if not an outright loss of control.

Increased Islamist Violence Against India, Increasing the Likelihood of Indo-Pakistani War: The Taliban and Al Qaeda are anti-American, yes. But they are equally determined to wage war against India’s secular, Hindu-dominated democracy. The Pakistani Taliban, whose momentum would be increased by Taliban success in Afghanistan, consist in part of Punjab-based, ardently anti-Indian Islamist groups, such as Lashkar-e-Taiba, which carried out the spectacular raid on Mumbai a year ago. The probable knock-on effect of a second Taliban revolution Afghanistan would be to increase the likelihood of irregular Islamist attacks from Pakistan against Indian targets—not only the traditional target set in Indian-held Kashmir, but in New Delhi, Mumbai, and other cities, as has occurred periodically during the last decade. In time, democratic Indian governments would be pressed by their electorates to respond with military force. This in turn would present, repetitively, the problem of managing the role of nuclear weapons in a prospective fourth Indo-Pakistani war.

Increased Al Qaeda Ambitions Against Britain and the United States: Deliberately, I would list this problem as fourth in severity in my initial straw-man forecast. Al Qaeda’s current capability to carry out disruptive attacks on American soil is very low. Still, it is absurd to think, as some in the Obama Adminsitration apparently have argued, that Al Qaeda would not be strengthened by a Taliban revolution in Afghanistan. Of course it would. Whether this strengthening would directly or quickly threaten the security of American civilians is another question. London might well be more vulnerable than New York during the ensuing five or ten years after an Afghan Taliban revolution. The Afghan Taliban are essentially inseparable from the Pakistani Taliban. Because of the size and character of the Pakistani diaspora in Britain, currently, there are about six hundred thousand annual visits by civilians between the two countries, a flow of individuals that is almost impossible to police effectively. Therefore, as recent terrorist-criminal cases in Britain document, bad guys periodically get through the border. By comparison, the post-9/11 American border is much harder for Pakistani- or Afghanistan-originated terrorists to penetrate. Still, in a civil war-ridden, Taliban-influenced Afghan state Al Qaeda’s playbook against the United States would expand. As 9/11 and the current creativity of the regionally focussed Taliban amply demonstrate, their potential should not be complacently underestimated. If they did get through and score another lucky goal, it is easy to imagine the prospective consequences for American politics and for the constitution.