"We are losing.

"Four years and two wars after the attacks of Sept. 11, 2001, America is heading for a repeat of the events of that day, or perhaps something worse. Against our most dangerous foe, our strategic position is weakening."

So begins Daniel Benjamin and Steven Simon's sobering new book, "The Next Attack." The authors, two of President Bill Clinton's counterterrorism aides, draw a persuasive and utterly frightening picture of the current state of America's war on terror.

They see more and more Muslims, many of whom had no earlier ties to radical organizations, enlisting in the struggle against the West, and they also point out the proliferation of freelance terrorists, self-starters without any formal ties to Al Qaeda or other organized groups. They see local and regional grievances (in places like Saudi Arabia, Chechnya and Southeast Asia) merging into "a pervasive hatred of the United States, its allies, and the international order they uphold." And they see in the Muslim world traditional social and religious inhibitions against violence and even against the use of weapons of mass destruction weakening as a growing number of radical clerics assume positions of influence.

Like the C.I.A. officer Michael Scheuer, the author (under the pseudonym "Anonymous") of the 2004 book "Imperial Hubris," Mr. Benjamin and Mr. Simon regard the American invasion of Iraq as a kind of Christmas present to Osama bin Laden: an unnecessary and ill-judged war of choice that has not only become a recruitment tool for jihadis but that has also affirmed the story line that Al Qaeda leaders have been telling the Muslim world - that America is waging war against Islam and seeking to occupy oil-rich Muslim countries.

The American invasion of Iraq toppled one of the Mideast's secular dictatorships, the authors write, and produced a country in chaos, a country that could well become what Afghanistan was during the years of Soviet occupation: a magnet for jihadis and would-be jihadis from around the world; a "country-sized training ground" (with an almost limitless supply of arms), where these recruits can train and network before returning home, battle-hardened and further radicalized. The authors add that "the sad irony" of the war is that Iraq now stands as an argument against democratization for many in the Middle East: "the current chaos there confirms the fears of both the rulers and the ruled in the authoritarian states of the region that sudden political change is bound to let slip the dogs of civil war."

In their last book, "The Age of Sacred Terror" (2002), Mr. Benjamin and Mr. Simon looked at how bureaucratic infighting and a lack of urgency on the part of government officials contributed to the failure to prevent 9/11. This volume, a sequel of sorts, similarly draws upon the authors' experience in counterterrorism and their inside knowledge of the national security apparatus, and it offers a grim cautionary lesson: "not only are we not attending to a growing threat, we are stoking the fire."

Though the authors' message is harrowing, they write in carefully reasoned, highly convincing terms. Much of their narrative ratifies judgments made in recent books by other intelligence experts and journalists.

Like Seymour M. Hersh ("Chain of Command") and James Bamford ("A Pretext for War"), Mr. Simon and Mr. Benjamin note the Bush administration's penchant, in the walk-up to the war, for cherry-picking intelligence to bolster its own preconceptions and for setting up alternative intelligence-gathering operations that would produce evidence supporting ideas that higher-ups like Deputy Defense Secretary Paul D. Wolfowitz and Defense Secretary Donald H. Rumsfeld already believed to be true.

Like George Packer ("The Assassins' Gate") and Larry Diamond ("Squandered Victory"), they suggest that the shocking lack of planning for a postwar Iraq stemmed in large measure from the administration's assumptions about an easy American triumph and its reluctance to listen to experts in the military and the State Department. And like Richard A. Clarke ("Against All Enemies"), they criticize the Bush White House for focusing on the number of Qaeda leaders captured or killed, instead of addressing the ideological underpinnings of radical Islam, which continually attracts new converts.

In laying out these arguments, Mr. Benjamin and Mr. Simon deftly flesh out now-familiar observations with new details and some revealing interviews with officials who worked with the administration or observed the decision-making process firsthand.

Writing that "the move to war" came "faster than has been reported," the authors quote one State Department diplomat who said that a small, secret meeting was held on the Martin Luther King Day weekend of January 2002 to plan the invasion; this official said, "the original idea was to go to war by Tax Day [April 15] '02."

The authors also quote Colin L. Powell's former chief of staff Lawrence Wilkerson - who recently made headlines with a speech in which he charged that America's foreign policy had been usurped by a small, secretive cabal within the administration - saying that the essential decision-making and planning for the Iraq war "was not taking place in the statutory process" of the National Security Council, "but in the parallel process run" by Vice President Dick Cheney, who had assembled his own national security staff of 14.

Much of the planning for the occupation, Mr. Benjamin and Mr. Simon write, was also done "out of channels," with officials "issuing directives without ever having their plans scrubbed in the kind of tedious, iterative process that the government typically uses to make sure it is ready for any contingency." They note, for instance, that the Principals Committee (President Bush's foreign policy cabinet) did not even meet "to discuss the disbanding of the Iraqi Army, which is now seen as one of the critical mistakes that has fed the insurgency."

In addition to increasing the jihadi threat by invading Iraq, the authors write, the Bush administration also squandered the post-9/11 years by failing to beef up homeland security sufficiently: in overemphasizing "the offensive side" of the war on terror, they argue, the White House has been diverted "from the imperative of a sound defense." The authors enumerate the many familiar targets that have not been secured (from railroads to seaports to chemical plants), and they also point to the reasons for these failures, including bureaucratic infighting; bungling at the F.B.I. (which has spent $581 million and "is still not close to having a functioning" computer system); delays in making key political appointments (in some cases, they write, over concerns about "the political loyalties of the individuals"); and a failure to look at tactical decisions within a larger strategic picture.

Indeed, one of the most disturbing charges that the authors level at the Bush administration is that it has failed to "look beyond Al Qaeda" and "recognize the multiplying forms that the jihadist threat is taking." This "serious failure of vision," they say, is the same one that prevailed in the pre-9/11 world: the misapprehension that "what terrorists do abroad has little consequence for national security, and, second, that only states can truly threaten us."

It is also a failure to comprehend fully the fallout in the Muslim world of the prison abuses at Abu Ghraib and the detentions at Guantánamo Bay; a failure to understand how the United States' actions in the Middle East play into a history of colonialism and decades of resentment; a failure to "halt the creation of new terrorists by dealing, to the extent possible, with those grievances that are driving radicalization."

In sum, Mr. Benjamin and Mr. Simon warn, these failures mean "we are clearing the way for the next attack - and those that will come after."