THE NATIONAL Commission on Terrorist Attacks Upon the United States did not begin its work under propitious circumstances. It was underfunded. It was given limited time but an enormous challenge: to deliver an authoritative account of the attacks and their aftermath and to issue recommendations to render America safer. And its commissioners were chosen in an overtly partisan fashion. Some of its hearings, in which commissioners seemed to play their assigned party roles, further stoked concern. All of which makes the more impressive the unanimity and comprehensiveness of the 600-page report the commission issued yesterday. The 10 members -- five Democrats and five Republicans -- issued a single document with no dissents and no additional views. Their report offers Americans a detailed history of the catastrophe that took place on Sept. 11, 2001; a probing account of the governmental failures that preceded it; and a useful analysis of the changes that have taken place since, as well as the changes that have not taken place. Most important is the commission's unwavering insistence -- coming at a time when America's commitment is starting to waver -- on the fundamental importance of countering Islamist terrorism in the coming generation.

The report was predictably trivialized by its reception in election-year Washington. Sen. Edward M. Kennedy (D-Mass.), for example, declared that it "make[s] clear . . . that the Bush administration did not give al Qaeda the high priority it should have had, either before or after 9/11." House Majority Leader Tom DeLay usefully added, "For eight years in the 1990s, international terrorism was at war with us . . . and we treated it like jaywalking."

In fact, the finding that both the Clinton and Bush administrations failed to fully appreciate the danger of al Qaeda before the attacks is one of the report's more obvious, and less interesting, historical findings.

Covering areas from al Qaeda's background and modes of operation, to the history of the plot itself, to the group's relationship with countries including Iran and Iraq, to the shortcomings of various governmental authorities -- notably including Congress -- the report will deeply enrich public debate and understanding of the attacks and the enemy America faces.

But the most important element of the commission's work is its willingness to think ambitiously about how this country still needs to change. The spasm of policymaking energy that followed the attacks is waning, and America faces a profound choice about whether to face the great challenge of confronting terrorism -- and organizing government accordingly -- or to drift back into complacency. The commission rightly urges not only fighting a war against terrorism but aggressively combating the conditions and ideas that give rise to violent anti-American Islamism; it urges, that is, that the United States promote democratic values and liberal education in nations where Islamist radicalism now seems the only alternative to authoritarianism.

The commission's recommendations for reform are far-reaching. It proposes creating a national counterterrorism center to manage intelligence and operations among different agencies and splitting the functions of the director of central intelligence between a director of the CIA and an overall intelligence czar in the White House. It will take months of debate to evaluate these ideas fully. But whether they are ultimately adopted or not, the report has clearly diagnosed some of the key problems that intelligence reform will have to address: specifically, how to ensure that someone is managing investigations across agencies, national borders and profoundly different legal systems. The quality of the commission's investigation and the strength of its evaluation of the bureaucratic problems should serve as a catalyst for a tremendously important discussion: Is America prepared to commit itself to this war for the long term, and how must society be organized to do so?