Najibullah Zazi, a 24-year-old Afghan and legal US resident was charged last week with planning to build and set off bombs after a long-term surveillance operation was reportedly blown by an imam recruited by New York police as an informant. According to the New York Times, the imam tipped Zazi that the authorities were interested in him, foiling any chance they might have had of getting details of the plot and identifying possible co-conspirators.

If the charges are true, Zazi, who prosecutors say got bomb-making lessons at an al-Qaida training camp in Pakistan, looks like the most dangerous terrorist caught in the US since 9/11.

According to prosecution documents, investigators found notes of "formulations and instructions regarding the manufacture and handling of initiating explosives, main explosives charges, explosives detonators and components of a fusing system" on Zazi’s laptop.

Zazi is alleged to have bought chemicals that could be used to make the explosive Triacetone Triperoxide - known as TATP and the substance for which the formula was found on his computer. Prosecutors even say they have evidence that he mixed chemicals in a hotel room in the weeks before his arrest.

TATP was the explosive used to such deadly effect by the London transit bombers in July 2007. It can be made from commonly sold chemicals including hydrogen peroxide and acetone - which Zazi allegedly bought in large quantities from beauty stores.

The ability to make such improvised explosives - and practice at actually doing so - is a key skill set for al-Qaida terrorists. Despite widespread concern about ‘virtual training camps’ on the Web and terrorist recruitment on the internet, almost every large-scale successful attack al-Qaida has carried out has relied on a key figure who actually got real, physical training, generally in a real, physical camp.

Making TATP bombs is a difficult, complex and dangerous procedure. Even those with training sometimes get it wrong.

Within weeks of the London transit attacks, a second wave of attempted suicide bombings - again by a cell with links to Pakistani training camps - failed only because the would-be bombmaker got the math slightly wrong in the formula.

Fantasy terrorism

The contrast between Zazi and the other suspects arrested last week is instructive. Both Michael Finton, the California-born convert who used the name Talib Islam, and Maher Husein Smadi, a 19-year-old Jordanian, were arrested after sting operations in which federal authorities supplied them with fake explosives.

They look much more like the kind of terrorist wannabes the FBI appears, at least from the public record, to have specialized in catching since 9/11 - “Fantasy terrorism cases,” as they have been called by Karen J Greenberg, executive director of the Center on Law and Security at New York University law school.

Finton allegedly tried to carry out his attack in a vehicle supplied by the FBI, using a bomb supplied by the FBI and in the company of an undercover FBI officer.

In the Smadi case, FBI undercover agents posed for months as members of an al-Qaida sleeper and provided him with an SUV wired with a fake bomb.

The efficacy, constitutionality and morality of such operations, where federal agents and their informants identify and then entrap potential terrorists, is a subject worthy of a column to itself.

For now, it will suffice to point out that, by contrast to these cases, one of things bothering the Zazi investigators is that they have not found the chemicals he bought - or any explosives he might have made with them.

Political hot potato

If Zazi really is the al-Qaida sleeper agent prosecutors allege, the question of how authorities were first tipped to his plot is likely to become a political hot potato.

For Obama’s more liberal or progressive supporters it is almost an item of faith that the sweeping surveillance authorities granted the federal government in the Patriot Act - cobbled together by the Justice Department and key congressional leaders in less than two months after the 9/11 attacks - are both invasive and ineffectual.

Three of those powers - roving wiretap authority; the so-called lone wolf amendment; and Section 215, which allows the government to obtain business records using an order from the secret Foreign Intelligence Surveillance Act (FISA) court - will expire later this year unless Congress renews them.

After weeks of silence, the Obama administration finally told lawmakers earlier this month that they supported a renewal of all the expiring powers, although Todd Hinnen, deputy assistant attorney general for national security, added in his testimony to a congressional hearing that the Justice Department was "ready and willing to work with members on any specific proposals” they might have to reform the law.

Pondering potential ‘calamities’

A glimpse of how Republicans are likely to deal with this debate was visible at the hearing, where Iowa GOP Congressman Steve King, referring to reports that Zazi’s plot had targeted the main New York City transit terminus, asked “What if this hearing was taking place in the middle of smoke and dust coming out of the ground at Grand Central terminal?”

Prosecutors have said they would use evidence obtained under FISA in the Zazi case, but it is not clear whether any of the expiring Patriot Act provisions were used in the case and Hinnen would not comment at the hearing.

But he did promise to provide King what the congressman called “a list of the plots that have been broken since the Patriot Act was passed and the successes of the Patriot Act,” so that lawmakers could ponder “the calamities that might have taken place had we not had the Patriot Act.”

If Democrats in Congress try to overhaul the Patriot Act, they may well find themselves fighting on a political terrain that favors their opponent, and even if they try and work with the administration, the result is likely to be politically messy.

On the other hand, there is an opportunity here to fix some of the things that are wrong with the Patriot Act, while preserving what is actually one of the few strategic advantages that the US has in its war with al-Qaida - its ability to conduct comprehensive electronic surveillance.

**Shaun Waterman is a senior writer and analyst for ISN Security Watch. He is a UK journalist based in Washington, DC, covering homeland and national security.