Our dad didn't let evil get the last word

Editor's note: Kerry Cahill is an advocate, writer and at-risk student educator. Keely Vanacker is a high school counselor and mother of two.

(CNN) -- When our father, Michael Grant Cahill, was murdered in the Fort Hood, Texas, shooting on November 5, 2009, we were barraged with the question, "What can we do?" People wanted to help, get milk, make us casserole and assist relatives with travel. Support was everywhere.

That support remains. In the wake of shootings in Newtown, Aurora, Tucson, Oak Creek, and too many more places, people are asking again, "What can we do?"

First, we must stop asking "why?" and start asking "why not?" In other words, what are we doing to prevent these tragic shootings?

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Keely Vanacker (left) and Kerry Cahill

These events are caused by a perfect storm of issues. These include the proliferation of assault rifles and clips of 30 to 100 rounds, access to mental health support or lack of it, and, most important, falling short in our efforts of prevention. It is a sinking ship, and we must start filling the holes.

Holes made by guns that shoot 45 rounds in 1 minute, like the semi-automatic rifle used in Newtown. Holes inspired by the glorification of the shooters in previous shootings. Their life-size faces on the cover of Time magazine, bought by you, and dominating the Internet sites you browse, while the fallen are left in the photo albums of their families. Holes made by the lack of help and understanding in our country's mental health. Holes made by the fact that the Newtown children are not the only children we have lost to mass shootings. They are the unfortunate 20 who made us realize the water is up to our throats.

The water is rising. What hole can you fill?

Can you think about prevention rather than reaction by supporting programs in our schools that encourage our children to look out for one another? Can you be honest about what it would take to defend yourself against an assault rifle? Can you pay attention to important legislation and contact your congressman and senators to show support or share your thoughts? Can you stop saying, "Glad it wasn't me" and start saying "What if it was me?"

We cannot continue accepting that "these things happen" and "you will never stop evil." Those statements ensure that more innocents will die.

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Our father charged a gun outfitted with 30-round extended clips and was shot six times. Dad never let evil get the last word. He never looked at a problem and thought it was hopeless. We must do the same, and we must be honest: sacrificing our pride and admitting that we, as a nation, have a problem.

We need training for our teachers and police officers. Training that doesn't just focus on how to react to shootings but knows the community and makes relationships that lead to safer communities.

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Programs such as Rachel's Challenge started after the Columbine shooting by the parents of the first student killed, Rachel Joy Scott. The Memorial Institute for the Prevention of Terrorism, started after the Oklahoma City Bombing, which trains police officers not just to recognize danger but how to create communities that are more aware. "Random actor" trainings, by Dan Korem, teaching educators how to identify possible mass shooters, focus on at-risk kids and help those students.

Gun sales are rising, but is the support for the families affected by some of those guns and commitment to prevention rising with it?

Here is the question we are haunted by: "What is wrong with us that it takes 20 children dying in one shooting to make us change?" And some of us still won't. We have to address the answers, and we have to have the conversation. Let's start fixing the problem instead of treating the symptoms.

The opinions expressed in this commentary are solely those of the authors.