The analysts for our intelligence services have a remarkably difficult job. Not only do they have to pick nuggets of important information from swamps of raw, often useless, and sometimes deliberately deceptive data, but they must then determine whether the data they gather constitutes a threat. To do this, they must set some threshold of sensitivity for the data. Two bits of information might not signal an impeding attack, but ten might. Of course, getting it right isn’t easy, as Jeff Jacoby notes in the Boston Globe:

Three weeks before the London bombings of July 7, Britain’s Joint Terrorist Analysis Center advised policymakers that “at present there is not a group with both the current intent and the capability to attack the UK.” That reassuring message from the country’s top intelligence and law enforcement officials, The New York Times reported last week, prompted the British government to lower its terror alert. Less than a month later, 52 people were murdered and 700 wounded when three subway trains and a bus were blown up in the worst act of terrorism the United Kingdom has experienced since the bombing of Pan Am Flight 103 in 1988.

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[T]he botched terror assessment raises a question for us, too: Which kind of intelligence failure is better — the kind that badly understates a threat, such as the one in London, or the kind that overstates a threat, such as the insistent warnings before the invasion of Iraq that Saddam Hussein was armed with weapons of mass destruction?

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So what kind of culture do we want intelligence agencies to foster among their operatives and analysts: one that tends to be overly focused on possible threats, or one that is more likely to downplay them? In general, would we rather take action to eliminate a danger that turns out to have been overstated — or take no action, and then be stunned when the enemy strikes?

Two years ago, I wrote:

In the case of the September 11th report, critics say intelligence analysts missed signals and failed to evaluate the threat thoroughly. Had the analysts been more vigilant, the argument goes, perhaps the September 11th attacks would have been prevented. And in the case of the pre-war intelligence on Iraq, the criticism is that intelligence analysts put too much credence in a few suspect pieces of data. In other words, the analysts were overly vigilant in assessing the threat. Of course, it is not possible to be too vigilant and insufficiently vigilant at the same time—but to the president’s critics, that’s beside the point. A political trap has been set that allows the carping to continue under all possible scenarios. Too hot, too cold...to some, it seems the porridge is always the wrong temperature as long as President Bush is serving it.

Because it is often difficult to distinguish suspicious intelligence reports from iron-clad information, human interpretation is required; inferences must be drawn. That’s why there are often disagreements in the intelligence community: different people looking at the same set of data can draw different conclusions. Such disagreements are not evidence of fraud, they’re evidence of varying levels of risk tolerance. That the Bush Administration is now less willing to accept a risk that was tolerated before is a direct result of the lessons learned on September 11th.

How risk-sensitive do we want our intelligence services to be? If we set the sensitivity threshold too high, we’ll get surprised by attacks like September 11th or the recent bombings in London. If we set the bar too low, we run the risk of relying on faulty information, which it appears we did with respect to Iraq’s WMD.

This is a discussion that we as a nation need to have. Indeed, this is a discussion we should have had by now. Unfortunately, it seems that the left these days wants none of the responsibility of putting forth possible solutions. Where is the left-wing plan for dealing with Islamist extremists who want to destroy Western society? We know that the left finds much fault in the United States, but in the nearly four years since the September 11th attacks, I still don’t know what the left proposes in response to the problem. (Sorry, I don’t accept doing nothing as a solution. We did nothing in response to terrorist attacks for years before September 11th, and look where that got us.)

It is legitimate to criticize President Bush, it is legitimate to criticize our past mistakes as a nation, but those criticisms seem to be the only thing the left can articulate. The are many self-proclaimed great thinkers on the left. Where are their ideas for confronting Islamic mass murder?