Parents who lose children, whether through accident or illness, inevitably wonder what they could have done to prevent their loss. When my son was killed in Iraq earlier this month at age 27, I found myself pondering my responsibility for his death.

Among the hundreds of messages that my wife and I have received, two bore directly on this question. Both held me personally culpable, insisting that my public opposition to the war had provided aid and comfort to the enemy. Each said that my son's death came as a direct result of my antiwar writings.

This may seem a vile accusation to lay against a grieving father. But in fact, it has become a staple of American political discourse, repeated endlessly by those keen to allow President Bush a free hand in waging his war. By encouraging "the terrorists," opponents of the Iraq conflict increase the risk to U.S. troops. Although the First Amendment protects antiwar critics from being tried for treason, it provides no protection for the hardly less serious charge of failing to support the troops -- today's civic equivalent of dereliction of duty.

What exactly is a father's duty when his son is sent into harm's way?

Among the many ways to answer that question, mine was this one: As my son was doing his utmost to be a good soldier, I strove to be a good citizen.

As a citizen, I have tried since Sept. 11, 2001, to promote a critical understanding of U.S. foreign policy. I know that even now, people of good will find much to admire in Bush's response to that awful day. They applaud his doctrine of preventive war. They endorse his crusade to spread democracy across the Muslim world and to eliminate tyranny from the face of the Earth. They insist not only that his decision to invade Iraq in 2003 was correct but that the war there can still be won. Some -- the members of the "the-surge-is-already-working" school of thought -- even profess to see victory just over the horizon.

I believe that such notions are dead wrong and doomed to fail. In books, articles and op-ed pieces, in talks to audiences large and small, I have said as much. "The long war is an unwinnable one," I wrote in this section of The Washington Post in August 2005. "The United States needs to liquidate its presence in Iraq, placing the onus on Iraqis to decide their fate and creating the space for other regional powers to assist in brokering a political settlement. We've done all that we can do."

Not for a second did I expect my own efforts to make a difference. But I did nurse the hope that my voice might combine with those of others -- teachers, writers, activists and ordinary folks -- to educate the public about the folly of the course on which the nation has embarked. I hoped that those efforts might produce a political climate conducive to change. I genuinely believed that if the people spoke, our leaders in Washington would listen and respond.

This, I can now see, was an illusion.

The people have spoken, and nothing of substance has changed. The November 2006 midterm elections signified an unambiguous repudiation of the policies that landed us in our present predicament. But half a year later, the war continues, with no end in sight. Indeed, by sending more troops to Iraq (and by extending the tours of those, like my son, who were already there), Bush has signaled his complete disregard for what was once quaintly referred to as "the will of the people."

To be fair, responsibility for the war's continuation now rests no less with the Democrats who control Congress than with the president and his party. After my son's death, my state's senators, Edward M. Kennedy and John F. Kerry, telephoned to express their condolences. Stephen F. Lynch, our congressman, attended my son's wake. Kerry was present for the funeral Mass. My family and I greatly appreciated such gestures. But when I suggested to each of them the necessity of ending the war, I got the brushoff. More accurately, after ever so briefly pretending to listen, each treated me to a convoluted explanation that said in essence: Don't blame me.

To whom do Kennedy, Kerry and Lynch listen? We know the answer: to the same people who have the ear of George W. Bush and Karl Rove -- namely, wealthy individuals and institutions.