And perhaps we can agree, too, that the United States did not have an adequate national security policy prior to September 11, 2001 – that the administrations of Bill Clinton, George H.W. Bush and Ronald Reagan all failed to recognize the growing magnitude of the terrorist threat, all did too little to prevent terrorist leaders from organizing, recruiting, training, plotting and carrying out attacks.

If you're still with me, we should be able to agree on another point: that it would be a mistake to return to pre-9/11 policies, to go back to viewing terrorism as a minor irritant that can be addressed through criminal prosecutions after the fact, quiet diplomacy and foreign aid.

Most of us probably now agree as well that America's intelligence gathering capabilities are insufficient to the challenges America faces. But let's acknowledge that this represents a very recent change of heart for most of us.

Last July, President Bush insisted that the intelligence he'd been receiving was “darned good.” That was not correct – as CIA weapons inspector David Kay has made clear. The consensus view of the U.S. intelligence community had long been that Saddam Hussein continued to possess stockpiles of weapons of mass destruction. Even the few dissenters from that view could not say what Saddam had done with the anthrax, ricin, sarin, VX and other WMD that we know he once possessed. And no one could offer any convincing reason why Saddam would have forced UN weapons inspectors out of Iraq in 1998 – and then destroyed his WMD, secretly and in violation of the obligations he'd undertaken in return for the 1991 ceasefire in the Gulf War. To this day we can only speculate on the answer.

The President's critics have actually agreed with Mr. Bush here. They, too, have argued that the intelligence community was supplying solid information -- while accusing the administration of having decided in advance to adopt a worst-case scenario. Those critics appear to have forgotten the history that made that judgment prudent.

For example, when U.S. intelligence analysts entered Iraq in 1991, they were shocked to learn that Saddam had come much closer to building a nuclear bomb than they had estimated. Seven years later, mistaken intelligence led President Clinton to destroy an aspirin factory in Sudan – analysts thought it was a facility for manufacturing chemical weapons. More recently, Libya turns out to have been further along toward nuclear weapons production than previously believed. Intelligence failed in regard to nuclear weapons development in both India and Pakistan. We still haven't figured out who spread anthrax attacks around the US Senate after 9/11. Nor have we ever solved the mystery of what organization or regime was behind the 1993 attack on the World Trade Center. And, astonishingly, as thousands of terrorists attended training camps throughout the 1990s in Afghanistan, Iraq and Lebanon, intelligence professionals either did not recognize the threat or failed to communicate the urgency. The list goes on.

All this brings us to the juncture where we – Republicans and Democrats, liberals and conservatives, neo-liberals and neo-conservatives and others – now divide: What should be the U.S. policy in response to terrorism, how should we relate to those who support and finance terrorism, what ought we to do about the ideologies that inspire terrorism?

So far, public discussion of these vital questions has been both scattered and confused. It has mostly centered on whether the threat from Saddam was “imminent” and whether a policy of “pre-emption” is justified. At the very least, this mixes two very different concepts.

Acting against an imminent threat is not pre-emption – it is simply self-defense. By contrast, pre-emption implies acting before a threat becomes imminent. It implies making a determination about an adversary's intentions, estimating – as best your intelligence allows -- his capabilities, and then taking action to prevent the threat from reaching maturity or “imminence.”

President Bush attempted to explain this idea in his 2002 State of the Union. “Some have said we must not act until the threat is imminent,” he said. “Since when have terrorists and tyrants announced their intentions, politely putting us on notice before they strike? If this threat is permitted to fully and suddenly emerge, all actions, all words, and all recriminations would come too late.” In other words, Bush was saying that Saddam was not an imminent threat but that removing him before he became one should be U.S. policy. Even so, the invasion of Iraq was not really pre-emptive: Rather, Saddam's longstanding refusal to comply with his obligations rendered the 1991 ceasefire null and void and justified the use of force as the only certain way to ensure that he was disarmed.

What's more, American credibility was at stake. Continuing to allow Saddam to defy the US and the international community sent a message. It reinforced the image of America as a “paper tiger.” Erasing that image has already brought benefits. Does anyone seriously believe that Libyan dictator Muammar Qaddafi would now be disarming as completely and transparently as he is had Washington let Saddam off the hook once again?

But if Iraq was not a pre-emptive war what would be? Suppose that at some point prior to 9/11 consideration had been given to invading Afghanistan in order eliminate al Qaeda and the Taliban. Proponents of pre-emption would have argued that it was enough to know that Osama bin Laden was planning attacks and had the resources to carry them through. Opponents of pre-emption would have argued that we must refrain from such intervention until and unless we could determine who the hijackers were and when they would be arriving –until it was clear the threat was imminent.

I think we should be able to agree on which policy is preferable. But if not, by all means let's start a serious debate.

Clifford D. May, a former New York Times foreign correspondent, is the president of the Foundation for the Defense of Democracies a policy institute focusing on terrorism.