They say everything changed on 9/11. No one can dispute that. But we didn’t learn anything.

The attacks on New York and Washington were a traumatic, teachable moment. The collective attention of the nation was finally focused upon problems that had gone neglected for many years. 9/11 was a chance to get smart—but Americans blew it.

The century of U.S. foreign policy that led to 9/11—supporting dictators, crushing democratic movements, spreading gangster capitalism at the point of a thousand nukes—should have been put on hold in the wake of 9/11. It wasn’t time to act. It was time to think. It was time to hope the world forgot how we supplied lists of pro-democracy activists to a young Saddam Hussein so he could collect and kill them, and forget the “Made in USA” labels on missiles shot into the Gaza Strip from U.S.-made helicopter gunships sold to Israel.

It was time, for once, to take the high road. The Bush Administration ought to have treated 9/11 as a police investigation, demanding that Pakistan extradite Osama bin Laden and others wanted in connection with the attacks for prosecution by an international court. Instead, the Bush Administration exploited 9/11 as an excuse to start two wars against defenseless countries that had little or nothing to do with the attacks. The media refused to question the wars. Democratic politicians, including Hillary Clinton and Barack Obama, voted in favor of them. Bush and company legalized torture and ramped up support for dictatorships in South and Central Asia and the Middle East.

By 2003 the world hated us more than ever. A BBC poll showed that people in Jordan and Indonesia—moderate Muslim countries where Al Qaeda had killed locals with bombs—considered the U.S. a bigger security threat than the terrorist group. September 11 was “blowback”—proof that the U.S. can’t wage its wars overseas without suffering consequences at home. But 10 years later, a Democratic president is fighting Bush’s wars as well as new ones against Libya, Somalia and Yemen. Now he’s saber-rattling against Syria.

American officials correctly inferred from 9/11 that security, at airports and in ports where container ships arrive daily from around the world, had been lax. But rather than act to close gaps in airport security, the new Department of Homeland Security created a gauntlet of police-state harassment. Perhaps the sheer quantity of goods arriving at American ports makes it impossible to screen them all, but we’re not even talking about the fact that we’ve basically given up on port security.

And what about air defenses? On 9/11 the airspace over the Lower 48 states was assigned to a dozen “weekend warrior” air national guard jets. Every one of them was on the ground when the attacks began—which could easily happen again. According to a 2009 report by the federal General Accounting Office on U.S. air defenses: “The Air Force has not implemented the 140 actions it identified to establish ASA [Air Sovereignty Alert] as a steady-state mission. … The Air Force has instead been focused on other priorities, such as overseas military operations.”

On 9/11 hundreds of firefighters and policemen died because they couldn’t communicate on antiquated, segregated bandwidth. “Our first responders,” admits FCC chairman Julius Genachowski, “still don’t have an interoperable mobile broadband network for public safety. Our 911 call centers still can’t handle texts or pictures or video being sent by the phones that everyone has.”

A lot changed on 9/11, but not everything.