Mom misspoke.

Pimentel's problem wasn't that he decided to covert to Islam. It's that he chose to become an Islamic extremist, taking online lessons from al Qaeda on how to make war on the West.

On Nov. 19, he was arrested for allegedly plotting a string of terrorist attacks in New York. His weapon of choice? The terrorist's friend, an improvised-explosive-device.

Even before the New York Police Department took down Pimentel, there was evidence of Islamist determination to strike the American homeland with IEDs. Think back two years to the infamous "Underwear Bomber" (It doesn't get more improvisational than that!). Or to last year's failed car bombing of Times Square.

Unfortunately, it's not that hard to become an IED manufacturer. Even if Pimentel had never clicked on the al Qaeda "Inspire" webzine and read the article "Make a Bomb in the Kitchen of Your Mom," many other sites on the Internet are happy to provide "how-to" bomb-making instructions.

To its credit, the Department of Homeland Security has not been flat-footed in its efforts to keep up with the IED threat. For several years now, the department has ramped up cooperation with other federal agencies, as well as state and local law enforcement and the private sector.

Since 2004, Homeland Security has provided more than 45,000 "locals" with expert bomb-prevention training. In 2007, the department established an Office of Bomb Prevention.

One of Homeland Security's most important initiatives is called TRIPWIRE -- Technical Resource for Incident Prevention. This program shares the latest information about IED threats including the materials and techniques used to assemble weapons.

Particularly important is information about "precursors" -- common or commercially available chemicals that can be used to manufacture powerful explosives.

This information helps businesses identify suspicious activity -- customers that ought to be brought to the attention of law enforcement agencies. Almost 12,000 users are authorized to use the TRIPWIRE website, and use it they do: more than 45 million times over the last five years.

Information exchanged via TRIPWIRE has been used for everything from helping investigate "lone-wolfs" like Pimentel to evaluating threats against the Grammy Awards.

The department has also improved coordination with the FBI. The agencies now offer joint access for private sector companies that operate most of the nation's critical infrastructure, from chemical plants in California to bridges in Cleveland.

The agencies make a special effort to speak with one voice through a joint initiative called the Bomb-Making Materials Awareness Program. Here, they have beefed up communications with local law enforcement and business to help them spot malicious activity at the retail level.

The idea is to identify would-be terrorists at the point of sale, rather than the point of boom.

Homeland Security's Office of Bomb Prevention and the FBI also manage the Joint Program Office for Combating Terrorist Use of Explosives, which coordinates all federal domestic counter-IED programs.

State and local jurisdictions have been active too. Many have ramped up their anti-IED efforts adding bomb squads, explosives detection canine teams and SWAT teams capable of better responding to this kind of terror threat.

All this effort has made the U.S. a harder target for IED attacks than it was before 9/11. Initiatives that stop attacks before they start never get as much press or credit as they deserve.

But, as Washington looks to cut homeland security along with the rest of the federal budget, it ought to think about where it gets the biggest no-bang for its buck.

James Jay Carafano is a senior research fellow for national security at the Heritage Foundation.