On Monday, July 20, our youngest left for Afghanistan. Tristan is 21 years old, and he joins his brother Paul, who is finishing a tour of duty in Iraq. So now we have two sons serving in two different countries during two wars.

These wars have become deeply personal. When we read about the increasing number of casualties, when we consider the families of every young serviceman or servicewoman killed or wounded, our hearts break for them -- and for ourselves.

Each story causes us to ask the most haunting of questions: "What if?"

Tucked away in a photo album, we have a picture taken years ago which shows two little boys standing at attention with coonskin caps on their heads and muskets at their side. Christmas gifts purchased at Fort Ligonier. In those days, they couldn't get enough of cowboys and Indians and G.I. Joes. They were two little boys who dreamt of becoming heroes and saving the world from the bad guys.

Now, years later, we have pictures of two handsome young men in uniform who, in their own way, still want to save the world from the bad guys. Undoubtedly, maturity has brought some ambiguity to their dreams. Exactly who the bad guys are, and how we can save the world from them, is much more difficult to discern. What I do know is that our two boys (they are always "our boys" to me), want to serve nobly in a virtuous cause. Their hearts are true.

But what about the hearts of those who send young men like Paul and Tristan into harm's way?

I came of age right after Vietnam. My wife's uncle, Michael Stoflet, was killed there. One thing we learned from Vietnam is the importance, even the necessity, of questioning the wisdom, judgment and integrity of those who decide to make war. To paraphrase C.S. Lewis, we have learned that there is no inherent contradiction between being a successful politician and an ass.

As hard as it is to fathom, we all know that our national leaders have in the past, and are capable today, of sending young men and women to die in wars that are unnecessary, unwinnable and unjust -- but politically expedient. Often, these decisions are made by those who have never fought in a war (Dick Cheney had five college draft deferments), and who make certain never to have one of their own children do the fighting.

Before a political leader decides to vote in order to send someone to war, he or she should ask themselves if they would be willing to send, and perhaps sacrifice, one of their own sons or daughters in the conflict. If the answer is questionable, then so is the war.

I was not a supporter of Barack Obama, but I did agree with, and admire, his opposition to the war in Iraq. After his election I breathed a sigh of relief. It relieved me to think that we had a person in the White House who was going to bring our troops home as soon as possible. As a father of two sons in the military, I was naturally relieved. This was change I could believe in.

Now I shake my head in disbelief. The man who promised to bring home the troops in a timely fashion is sending 24,000 more troops into a questionable war in Afghanistan, which many experts believe is militarily unwinnable. Even the Post-Gazette editorial board, an ardent Obama supporter during the campaign, questions the wisdom of sending more troops.

Last month was the deadliest for Americans fighting in Afghanistan. Behind each of those deaths is a family whose hearts are breaking. These families are proud of their sons' and daughters' service for our country, but they, and all Americans, want to know that these sacrifices were absolutely necessary in the struggle for a just cause.

The Obama administration has put on a full-court press for passage of a bill to overhaul America's health-care system. President Obama spent time on television explaining what must happen and why.

The same full-court press needs to occur in order to explain why we must still be in Afghanistan. Anything less than this is a disservice to our nation and to those who serve this nation in our military -- and their families.

Our sons, like hundreds of thousands of others, are serving their country with honor and integrity. We support our troops. They want to stop the bad guys from doing greater harm in this world. And there really are some nasty people hellbent on furthering their purposes. They must be stopped, but exactly how fighting a war in Afghanistan will keep us safe from terrorists in Pittsburgh or Peoria or Pasadena needs to be clearly explained.

Is this war absolutely necessary for our freedom and well-being as a nation? Will this war keep weapons of mass destruction out of the hands of terrorists? Will the world be a safer place by the sacrifice of so many?

Mr. President, this is your war now. You must explain.