The main issue — that the White House used phony intelligence reports to stampede a wavering Congress into an unprovoked, unprecedented and ultimately tragic invasion of Iraq — got lost somewhere.

Inevitably, the names of Plame and Wilson will dissolve into footnotes. But decades from now history will remember “the Italian letter,” shorthand for the fabricated documents at the heart of the Plame affair.

The most important of them purported to be a letter from the Niger foreign minister to Iraq agreeing to sell it 500 tons of uranium.

As it turned out, the sheaf of documents was the creation of “rogue” Italian military intelligence agents, according to stories so far.

Why Rome? And why would they do it?

The agents’ motivation remains unclear. But it is a fact that they worked for a secret service that has long been highly politicized and closely connected to right-wing government officials.

And that in 2002, moreover, when the phony documents arrived at the U.S. Embassy in Rome, the agents served under Italian Prime Minister Silvio Berlusconi, one of the Bush administration’s very few European allies on Iraq.

In a fascinating book to be published April 3, investigative journalists Peter Eisner and Knut Royce compare the creation of “the Italian letter” to the so-called Zimmermann Telegram of 1917, the leak of which pushed the United States into World War I.

“A letter may not start or avert a war,” they write, “but it can have a profound effect.”

In 1917, Americans were profoundly wary of involvement in the European war when British intelligence intercepted a telegram from German foreign minister Arthur Zimmermann to Mexico, which promised help in regaining its lost territories in Arizona, New Mexico and Texas if it would join in a military alliance against the United States.

Its publication outraged Americans and prompted President Wilson to ask Congress to declare a “war to end war . . . a war to make the world safe for democracy.”

Only later did Americans learn what Mexican leaders had recognized right away: That Zimmermann’s proposal was absurd, militarily speaking, with a powerful America on its border and Germany so far away.

Likewise, Iraq already had tons of uranium, and despite almost 20 years of trying, its scientists hadn’t figured out how to make it into a bomb. They quit trying in 1990.

The leak of “the Italian letter,” along with the Bush administration’s constant spectre of Iraqi mushroom clouds over New York, obscured all that.

But at least Zimmermann’s offer to Mexico was real, as were German U-boats attacking U.S. shipping.

The Italian documents were entirely concocted.

Which is what Joe Wilson, a former ambassador in Africa and Iraq, deduced after his secret mission to Niger in early 2002—and why he had to be neutralized.

Spy Story

Eisner, an editor at The Washington Post, and Royce, a distinguished former investigative reporter for Newsday, meticulously follow the circuitous trail of “the Italian letter” — also the title of their book — from a break-in of Niger’s embassy in Rome through the back doors of intelligence agencies in France, Britain and the U.S. It’s an extraordinary inside tour.

Putting aside the White House’s perfidy in the affair, what emerges is a portrait of a CIA that had become too big, bureaucratic, sloppy, lazy and perhaps — in the case of its top leaders — too craven to force a showdown with Bush administration over its manipulation of the documents.

America’s premier spy agency could have stopped the hoax in its tracks, Eisner and Royce write, back in 2002.

The verbatim text of one of the documents contained “contained numerous errors — dates were wrong, officials were misidentified, and their positions outdated — easily detectable with a simple fact-check on Google.”

Eventually, top State Department intelligence and CIA officials recognized the documents were fraudulent, but — in the kindest possible interpretation — they underestimated the White House’s intent on using them.

It’s not over. The pile of forged documents sits in the White House’s path like an improvised explosive device, one of the roadside bombs that are killing American soldiers in Iraq.

The Senate Select Intelligence Committee is following up on testimony in the trial of I. Lewis “Scooter” Libby, convicted for his role in the smear campaign against Joe Wilson, according to a knowledgeable source who cannot be identified.

And Rep. Henry A. Waxman, D-Calif., is still pursuing answers to the affair from Secretary of State Condoleeza Rice, who treated his 16 previous inquiries like flyers on her windshield when he was in the minority.

On March 12, the persistent, bald-pated Californian sent his 17th demand for answers to Rice, he was chairman of the House Oversight and Government Reform Committee.

Now he has subpoena powers, which he may well need following the State Department Assistant Secretary Jeffrey T. Bergner’s response of Apr. 17, saying that, considering all the information already available to the committee, “there would be little purpose in Secretary Rice's testifying at a hearing on these issues.”

Now he can dust off Plame’s chair for Rice.

Meanwhile, some seasoned federal investigators remain incensed at how the Niger affair petered out with Libby’s trial for perjury.

A ranking counterterrorism veteran scoffed at the idea that the White House was victimized by the document scam, as Rice has maintained.

“We were manipulated by a foreign intelligence service? Gimme a [expletive] break,” he said.

“The documents were fabricated, in my opinion, by our Casa Blanca [White House], using the Italians as a conduit,” he said. And the Bush Justice Department, he said, put what should have been a major criminal investigation into the hands of inexperienced counterintelligence agents who couldn’t even manage to find the mysterious European spy at the heart of the affair.

The administration has dismissed such notions.

“We did not know at the time,” Rice insisted on Meet the Press in June 2003, “no one knew at the time, in our circles — maybe someone knew down in the bowels of the agency, but no one in our circles knew that there were doubts and suspicions that this might be a forgery.”

That’s false, the evidence now shows.

But the secretary of State may soon have an opportunity to repeat, or revise, her remarks — under oath — for the Waxman panel, in Room 2157 of the Rayburn House Office Building, the same place Valerie Plame told her side of the story.

Jeff Stein can be reached at jstein@cq.com.

SpyTalk’s book shelves are groaning. Here are just a few recent noteworthy arrivals:

• Cuba Libre:Scott W. Carmichael, the senior security and counterintelligence investigator who busted a Cuban spy inside the DIA in September 2001, tells how he did it in “True Believer: Inside the Investigation and Capture of Ana Belen Montes, Cuba’s Master Spy” (Naval Institute Press). Carmichael “has also been investigating attempts by foreign intelligence services to penetrate DIA operations worldwide for nearly twenty years,” a press release says.

• Bald Faced: Lie detectors are bogus to some, but judge for yourself in “Gatekeeper: Memoirs of a CIA Polygraph Examiner,” by John F. Sullivan, who “fluttered” subjects, as the spooks say, for 31 years. “It is also a window to the often acrimonious and sometimes alarming internal politics of the CIA,” the blurb from Potomac Books promises.

• Hez to Ya: From Boston University Press comes professor Augustus Richard Norton’s “Hezbollah: A Short History,” which arguesthe U.S. is “getting it wrong” in its approach to “Janus-faced” terrorist organizations that offer social services and hold seats in parliament, as Hezbollah does in Lebanon.