Oklahoma City (1995--168 killed), Columbine High (1999--12 killed), Virginia Tech University (2007--32 killed), and now Ft. Hood (13 killed). What do these memorable places have in common?

They are each sites where Americans killed Americans in a culture whose violence extends from here to places like Iraq and Afghanistan. They are symptoms of a deep problem not likely to disappear without serious intervention.

Connections exist among the violence here at home and American violence in wars abroad, which indicate a pattern. These incidents are among growing signs that we should analyze carefully, now, before additional warnings happen and perhaps even worsen. The root causes of such eruptions should be studied.

Responses to Ft. Hood could develop into what is described as a "tipping point" in the best-selling book of that title by Malcolm Gladwell. Others describe such a time as a "turning point." Perhaps we could turn away from such extreme violence.

Where might terror strike next and who might be the perpetrator(s) and victims? More students, soldiers, or some other group? How is such domestic terrorism bred and what can we do to interrupt it? It's time to look inside, rather than seek outside scapegoats. Raising haunting questions is more important now than rushing to facile answers and seeking revenge.

At Oklahoma City an anti-government activist detonated the bombing of a federal building. At Columbine two high school students pulled triggers on other students and a teacher. At Virginia Tech a college student killed other college students. At Ft. Hood the suspect is an Army physician who killed five other psychotherapists and an additional eight people, and wounded some 31.

What does it say that a mental health professional seems to have endured so much trauma that he broke under the stress and engaged in a mass shooting? It is too easy to just blame these individuals.

As a former Army officer whose military family gave its name to Ft. Bliss, Texas, who was raised partly near Ft. Hood, this massacre struck close to home. As a college professor, when I read about shooting at schools, I think about my responsibility to help protect students.

The American shoot-‘em-up approach to solving problems is not new, especially in Texas and the remaining Wild West. These recent tragedies have lessons to teach us, so that the likelihood of other such incidents can be reduced.

Rather then merely indict the individuals that committed these heinous crimes, we could benefit from looking beyond them to consider our own responsibilities as citizens to reduce such violence and improve the context that spawns it.

It is easier to demonize the killers, rather than try to understand why these desperate men felt driven to such violence that would likely take their own lives or lead to extreme punishment. Their anguish and agony must have been substantial.

Punishment of the perpetrator alone is unlikely to break the cycle of violence that Americans commit here at home and carry abroad. A careful study of patterns would be more helpful.

The recent violence at Ft. Hood and in the town of Killeen, where it is located, is not new. The area "has been beset by crime and violence since the wars in Afghanistan and Iraq began," according to the "New York Times" on Nov. 10. "Reports of domestic abuse have grown by 75 percent since 2001," it continues. Soldiers come home from combat and beat their wives, sometimes to death. 76 suicides by personnel assigned to Ft. Hood have occurred since 2003.

There is no one to blame other than Americans. We did it. Not Muslims, Arabs, or outside "terrorists." Not external enemies. "We have met the enemy, and it is us," asserts a famous line from a Pogo cartoon from my childhood. It is time for us to reflect on the context that breeds such self-destructiveness.

From the day after the Ft. Hood massacre on Thursday to Sunday I mainly read and clipped many articles, while continuing my regular life. I was especially struck by the heroism of civilian Sgt. Kimberly Munley, who bravely took the shooter down, even as she went down with four bullets in her body.

It was not until Sunday night that I really felt the horror. I became numb, immobilized, depressed.

Fortunately, earlier that day I emailed my Sonoma State University students toput Ft. Hood on the lesson plan for my "War and Peace" class. I wanted to gently encourage them to get beyond denial to express their feelings, develop opinions, and engage in critical thinking. The students were attentive and thought deeply about the implications of Ft. Hood and what it reflects about us as a nation and our future.

"It takes a little while before the grieving starts," reads the last quotation in a Nov. 8 article in our local daily "The Press Democrat." It opened me to my own grief. The words are those of Col. Bill Rabena, who runs the new post-Ft. Hood massacre Spiritual Fitness Center. It offers counseling, soothing music, a religious library and meditation space, among other services, to help survivors cope with psychological trauma.

While I was in the Army during the l960s and the American Wars in Vietnam, Cambodia, and Laos we did not have such centers. So I have felt mainly alone during the some 40 years after my discharge and having to de-militarize myself and deal with my own trauma. I am still recovering and easily triggered, especially by loud sounds.

We need to work to enhance the safety of our students, soldiers, and citizens as a whole, or future similar incidents are likely. Public places-such as schools, government buildings, and even military bases-have become less safe during this 21st century.

Perhaps the Ft. Hood massacre can awaken us to the pain and suffering of our military personnel and the lives that they touch overseas and in their families. On the other hand, a Nov. 16 "Newsweek" column on the new book "American Homicide" by Ohio State professor of history and criminology Randolph Roth notes "that gun and ammunition sales are up nearly 50 percent from a year ago." What does that say about the state of our union and our future?

Now is a time to grieve our national losses and work to minimize such losses in the future. Such collective grief can inform and educate us.