Why haven't we been attacked since 9/11? The Bush administration has suggested two main reasons: dumb and dumber.

Argument #1: "we're fighting them over there so they don't attack us over here." Yes, and the Tooth Fairy is real. This argument takes the prize for being both misleading and stupid, suggesting that Iraq's civil war and regional instability are offset by that invisible fence in Anbar province that magically corrals the world's terrorists and keeps them right where we want them.

Argument #2: "We've hardened the target by making dramatic improvements in homeland security, intelligence, and counterterrorism here at home." This one sounds more reasonable on the face of it. We've seen a number of changes since 9/11. Among them: The FBI has doubled its analyst corps, the intelligence budget has increased an estimated 25%, and counterterrorism "fusion" centers are popping up like mushrooms--with more than 40 of them across the U.S.

Two problems here. The first is your view of progress. Government officials love to report about the half full glass. It's the half empty part that worries me more.

Take the FBI: Yes, the Bureau has twice as many analysts today as it had on 9/11. But analysts --the lifeblood of domestic intelligence — are still treated as second class citizens. 9/11 Commission poo-bahs Tom Kean and Lee Hamilton made this point in last Sunday's Washington Post. The Justice Department's Inspector General also highlighted the problem — with data, and specific recommendations — in its April 2007 report. At Quantico, new analysts and special agents still don't train together (unless you count one 4-hour exercise over a several week course). And as of last year, I'm told they even wore different colored shirts (analysts wore tan, agents wore blue). Nothing says "not on the same team" more loudly. Hiring more analysts sounds good. But dot connecting can't be valued unless the dot connectors are.

The more alarming problem is logic.

Just because we haven't experienced tragedy does not prove we are doing things right. This is causality 101, and it's something we drum into UCLA MPP students in their first year. Causal connections have to be examined, not assumed, or you'll get into trouble.

My 92 year-old grandmother, whom I love dearly, still drives a car in Miami. Incredibly, she's had no accidents since 9/11. But I'd never conclude that her driving acumen is responsible for her traffic record, or that she's become a better driver over the past 6 years.

The "we haven't been attacked" argument suffers from the same logical weaknesses. Why haven't we seen another 9/11 since 9/11? A million possible reasons. Many it's al Qaeda's long planning cycles. Maybe it's the disruption of al Qaeda Central in Afghanistan. Maybe it's sheer dumb luck. Maybe it's those ziploc bags at the airport. But the most dangerous explanation is the one that works backwards, inferring causes from outcomes and suggesting success when there may be none.