On April 19, 1995, the Alfred P. Murrah Federal Building in downtown Oklahoma City was bombed by homegrown terrorists Timothy McVeigh and Terry Nichols, killing 168 and injuring nearly 700. William Morrow releases Oklahoma City: What the Investigation Missed—and Why It Still Matters by investigative journalists Andrew Gumbel and Roger G. Charles. Tip Sheet spoke with Gumbel on the 17th anniversary of the bombing.

How'd the project come together? Roger Charles has been with this story from nearly the beginning, how did you get involved?

I first wrote about the bombing in 2001, on the eve of McVeigh's execution, and have been fascinated by it ever since. The launchpad for the book was gaining access to a large quantity of previously unpublished documents, and as the project went forward the number of these documents grew exponentially. By the end we had access to the entire archive of documents that the government presented at trial—about a million pages in all—as well as a number of vital documents that were not included in court records.

Why now—has there been a major break in recent years?

Aside from the documents, the other big development was Terry Nichols's decision to go public. He's been writing about the bombing from prison since 2004, but almost none of his writings have seen the light of day until now. Including his very detailed answers to hundreds of our questions, he's written the equivalent of a decent-sized book himself. His writings include some frank confessions he did not previously make—for example, a vivid description of building the bomb with McVeigh—and answers to questions the government was never able to provide. He told us, for instance, that the missing rear license plate from McVeigh's getaway car was given to him three days before the bombing. McVeigh did not lose it, as many have speculated, but very deliberately removed it—a decision that ultimately led to his arrest by an alert Highway Patrolman 90 minutes after the explosion.

The bombing was 17 years ago this week—did the elapsed time make your investigation more or less easy?
The passage of time made it much easier to interview the principal players in the investigation and trials, because many of them have now left government service and are much freer to speak. They were invariably frank and, in many cases, frustrated and angry about the opportunities that were lost, the leads that were not followed and the inter-agency turf wars that created mind-boggling obstacles to unearthing the truth. As authors, we don't have subpoena power or other resources making a proper re-investigation of the case possible. When the FBI chose, at the time, not to interview a number of people on the radical far right on whom they had promising leads, a lot of doors closed, unfortunately

How much of the intelligence failure on 4/19 was systemic?

The failure was absolutely systemic. The FBI was barred by Attorney General guidelines from conducting intelligence operations—a holdover from the Watergate era—and was reluctant to open cases on the radical far right as a result. The FBI and the ATF weren't talking to each other and frequently held each other in contempt, so there was no information-sharing. The debacles at Ruby Ridge and Waco—instances of overreaching by federal law enforcement in the early 1990s that resulted in dozens of needless deaths and stirred up considerable anti-government hostility—made both agencies gun shy. Agents who knew the subject and were alert to the dangers were generally ignored by their superiors who thought a bunch of marginal wackos could never amount to much, no matter how alarming their rhetoric or the weapons they were amassing on the gun show circuit.

Had our approach improved by the time of 9/11? Has it improved much since?

The feds became much more attentive to the domestic threat after the bombing, but the FBI's allergy to intelligence work persisted until 9/11, as did the inter-agency rivalries. It's more difficult to judge the contemporary FBI, because the public record is not as rich, but there is certainly a question about the institutional knowledge that now exists to combat threats from the radical right. A lot of experienced agents were switched to international investigations after 9/11, and it's not clear who has filled the void. And the FBI and the ATF still hate each other.

Are the kind of virulent subcultures you describe in Oklahoma City still a threat today, in OKC and/or elsewhere? Have authorities learned the right lessons?
The number of hate groups has exploded since President Obama took office. We have a large number of combat-hardened veterans, some traumatized by what they experienced in Iraq and Afghanistan, returning to a depressed economy. Inevitably a percentage of them will gravitate toward extremist ideologies, as McVeigh did after his service in the Gulf War. Access to deadly weaponry, meanwhile, has never been easier. Those subcultures are very much a threat, and have been identified as such by the Department of Homeland Security, the Southern Poverty Law Center, and others.

What do you want readers to take away from Oklahoma City?
Too often people—not just in the United States—tell themselves consoling stories to make traumatic events like the Oklahoma City bombing seem more digestible. It's easy to say, this was just a couple of kooky guys from the heartland who did something stupid, got caught and paid the price. The book shows the plot almost certainly went wider, law enforcement blew its chances of preventing the bombing and made serious mistakes in investigating it. The justice system was too interested in securing convictions against the two principal defendants to want to identify what was missed. This is a story with a lot of moving parts and there is no one simple takeaway. But it is clear the country's institutions failed in significant and serious ways, and we ignore those failures at our continuing peril.