When I started as ombudsman in November 2000, it was at the beginning of a deadlocked presidential election, a historic struggle that was to last 36 days and be settled by the Supreme Court. Less than a year later came Sept. 11. Then came wars in Afghanistan and Iraq.

Those last three events have turned out to dominate many of these columns, perhaps to a fault. The Post touches our lives in many other ways that probably deserved more attention than they got from me.

Iraq, in particular, has proved impossible for me, along with many readers, to put aside and move away from. I keep coming back to it, in part, because readers keep coming back to it but also because I cannot think of a story in the past 40 years that offers more warning signs for journalism and for the role of the press in our democracy. And it's not just the press for whom Iraq should loom large. It is also Congress, the Cabinet, the civil service, the intelligence community and the military leadership.

There is no bigger story than war. And a war whose major premise -- the threat from Iraqi weapons of mass destruction -- turned out to be unsupported is an even bigger story. That the administration presented this threat to the public with such a strong, yet false, sense of certainty -- including the imagery of mushroom clouds -- is an even more important lesson for all of us about big but not well-examined decisions. How did a country on the leading edge of the information age get this so wrong and express so little skepticism and challenge? How did an entire system of government and a free press set out on a search for something and fail to notice, or even warn us in a timely or prominent way, that it wasn't or might not be there?

Since the war began, many other questions have been raised about other prewar assessments. But the key question for journalists is how the process of vetting the main prewar rationale for sending Americans into a war took place, or failed to take place.

This is not a political question. It would need to be pursued if these events had taken place under a Democratic administration, as was the case 40 years ago when a murky event, or non-event, in Vietnam's Tonkin Gulf also went largely unchallenged and provided the peg for another president to commit the United States and its military to a long and costly war.

One can only hope that history will show that some good will come from the invasion of Iraq. Things don't look good now. Retired Army Lt. Gen. William E. Odom, who headed the National Security Agency in the Reagan administration, said last month that the invasion of Iraq "will turn out to be the greatest strategic disaster in our history." Let's hope not, but whatever happens, the issue for journalists is how they performed in the run-up to war.

Much has already been written -- including about two dozen columns of mine -- about the press and the general failure to challenge in prewar coverage. As I look back at the past five years in this job, that is by far the single most important and most disappointing performance by the press, including The Post. And The Post -- along with the Los Angeles Times and the Knight Ridder/Tribune News Service -- was among the best. But it was nowhere near good enough.

The Post is surely one of the top newspapers in the world, and I think it has been on something of a roll during the past two years or so in terms of especially solid and revealing coverage of many subjects that some would prefer not to be covered. But the period before the Iraq war is so important because it was one of those historic, chips-are-down moments when a newspaper, especially one as important as The Post, must commit to using its resources and exercising its responsibilities to probe fully what the government is saying and doing.

As I've noted in previous columns, The Post contributed a fair number of stories that raised questions about the issue of weapons of mass destruction. But too many of these were placed well inside the paper. Several other stories that challenged the official wisdom and unfolded in public were either missed or played down. I have attributed this mostly to what seemed to me to be a lack of alertness on the part of editors who at the time were also undoubtedly focused on preparing for the coming war.

Editors up and down the line are the key to this and, in my view, at times are the weak link between reporters and readers. Reporters are as good as they've ever been. But editors set the tone. They should be experienced and as informed as reporters. They need to contribute to, and transmit, the sense that there are very important stories out there -- whether war or health care or budget deficits or other subjects that affect our lives and future -- and that there is a determination and commitment to get to the bottom of them in a timely fashion.

The prewar Iraq situation also provided a unique test because the subject was complicated and classified. The administration was enormously skillful and disciplined at getting its message across while keeping other things secret. It made effective use of our concerns and reactions to the scary post-Sept. 11 world. Some journalists or news organizations may have been intimidated by the atmosphere. I don't think The Post was.

Rather, it seemed to me that editors didn't have their eye on, and didn't go for, the right ball at the right time. It's a lesson that ought to be etched in the culture here as deeply as Watergate.