The Labor Day discussions on NPR's "Talk of the Nation" were a varied lot: exercise, Iraqi refugees, the questions children ask parents.... And there was this one: When is it time to stop marking the anniversary of tragedies and move on?

Next Tuesday is the sixth anniversary of the 9/11 terrorist attacks. This year, the anniversary falls on the same day of the week as the tragedy. And in Rochester, some of these late-summer days have been very like that day: cool, sunny, crystal bright. The memories and the dread come back. When should we put them behind us?

For many Americans, no doubt, it is past time to move on. But for many others, even for those of us who lost no family members or friends in the attacks, the pain is still too real, too fresh. And September 11 will again be a day of mourning.

It will also be a time to mark the tragedy that has grown out of that day: the deception and delusion that led this country and too many others into a misguided, poorly planned, and criminally executed war.

In the fall of 2001, as the shock of the attacks swept over us, the rest of the world grieved with us. Many of the world's leaders stood with us.

Now, after the invasion of a country that posed no threat to us, after the lies and the torture, the deaths and the maiming, after the trampling on international law and principles of human rights and human dignity, we are despised by many, trusted by few.

The war has stretched our armed forces thin, has cut leaves short, sent men and women back for additional tours too soon. And the war's financial cost has kept us from addressing critical needs at home - as it will do for years to come.

(Not everyone has come out a loser in Iraq, and the media have begun to expose some of the winners, Halliburton only one of them. Recent accounts worth reading include Rolling Stone's September 6 "The Great Iraq Swindle" and the New York Times' August 31 story on contractors and bribery.)

Our closest, misguided ally, Great Britain, has begun pulling its troops out of Iraq. And our own president has started hinting at troop reduction. He has, apparently, begun looking for a way out that will let us boast and swagger as we go.

When we leave Iraq, we will leave pain. And we will leave a region of the world that has become more volatile, not less, because of our actions.

We head toward the sixth anniversary of 9/11 engaged in a national debate that we shouldn't have had to have: what is the least painful way to get out of Iraq? How can we do the least harm? Is there any way to avoid the escalation of civil and tribal war?

Certainly, we have to leave. We can not "win"; Iraq was not ours to win. And we can not force democracy on anyone, anywhere.

How we leave, and when, will be a central issue in the presidential campaign, as it should be. But every candidate knows there is no easy solution. And whoever moves into the White House in January 2009 will be faced with one of the hardest challenges of any president in recent history.

In a New York Times column on Monday, Roger Cohen quotes former National Security Adviser Brent Scowcroft on the damage done to the nation: "Historically," said Scowcroft, "the world has always given us the benefit of the doubt because it believed we meant well. It no longer does."

How long should we mourn? When is it time to stop marking the anniversary of the terrorist attacks? When is it time to move on?