President-elect Obama's announcement of his (mostly) stellar national security team coincides with the release this week of a bipartisan commission report with this chilling assessment of the most important challenge that team faces: "Without greater urgency and decisive action by the world community, it is more likely than not that a weapon of mass destruction will be used in a terrorist attack somewhere in the world by the end of 2013."

Perhaps the commission, former Defense Secretary William Perry, and other experts who have issued similarly dramatic warnings are crying wolf. Perhaps the likelihood of any terrorist group getting a nuclear bomb is "vanishingly small," as Ohio State political science professor John Mueller has forcefully argued. Or perhaps it's closer to 30 percent over the next 10 years, as Matthew Bunn of Harvard's Kennedy School estimated last month in "Securing the Bomb 2008."

Our way of life may well depend on catching nuclear or biological terrorists before they can strike.

Whatever the odds, if terrorists ever smuggle a crude, Hiroshima-sized nuke into, say, Manhattan, the immediate death toll could exceed 500,000. And the ensuing panic could threaten our constitutional system, spur evacuations of major cities, kill international trade, bring the worst economic depression in history, and perhaps usher in a new dark age worldwide.

This prospect puts into perspective the efforts of many human-rights activists, Obama supporters, and journalists to weaken essentially all of the government's most important tools for disabling terrorists before they can strike.