For years, advocates of climate-change legislation have struggled to find a sales pitch that will sway even the most hardened of skeptics. Polar bears, green jobs, urgent pleas to think of the grandkids … none of them have quite done the trick. But recently, a new argument has come to the fore: the national security case for cutting carbon emissions.

On May 28, George Tenet delivered for the Bush administration. Nearly two months had passed since the fall of Baghdad. U.S. forces had turned up no weapons of mass destruction (WMD) in Iraq, raising the specter of gross misjudgment on the part of the U.S. intelligence community and allegations of presidential dishonesty. But, that day, the CIA announced that two trailers found in northern Iraq the previous month were actually mobile biological-agent production facilities.

Foreign policy is always difficult in a democracy. Democracy requires openness. Yet foreign policy requires a level of secrecy that frees it from oversight and exposes it to abuse. As a result, Republicans and Democrats have long held that the intelligence agencies--the most clandestine of foreign policy institutions--should be insulated from political interference in much the same way as the higher reaches of the judiciary. As the Tower Commission, established to investigate the Iran-Contra scandal, warned in November 1987, "The democratic processes ...