As a grandfather and a member of Congress, I have a responsibility to speak up for those families and families like them across the country.

On Friday in Tucson, police were at my grandchildren's school as a precautionary measure. It was an important action to ensure their safety, but nonetheless scared my little ones and their parents. We must not stand by and let our children be put in harm's way again.

Sadly, those of us in Tucson understand what the people of Newtown are going through today and what lies ahead. We know that it is impossible to make sense of the senseless. And we know that in the end, a community tragedy such as this has the potential to bring people closer together in the common search for answers.

I don't have all the answers. There is no single law that we can write, no single regulation that we can impose, no single process that we can put in place that will address the many problems that come together to cause such a horrifying tragedy.

But some of the pieces are laid out before us.

I am a strong supporter of the Second Amendment and the right to bear arms -- but we must take action to deal with the easy availability of assault weapons and extended magazines.

We must take action to prevent people who are a danger to themselves and others from getting access to these weapons.

We must not wait any longer to address this crisis. But we must also recognize that these issues are not the only pieces in a complex problem to which there is no single answer.

Untreated serious mental illness and access to weapons with heavy firepower are the underlying causes in a number of these violent incidents. It is well-known now that this is what caused the tragic January 2011 shooting near Tucson in which six people were killed and 13 others -- including then-Rep. Gabrielle Giffords and me -- were injured.

Information is emerging about the mental health of the Connecticut gunman. It is irresponsible to dismiss untreated mental illness as a factor in several recent mass shootings. We have it within our power as a nation to resolve these issues. It is important to remember that the overwhelming majority of people dealing with mental illness are not violent.

After I was wounded almost two years ago, I took steps to address the mental-health issue head-on. My family and I founded the Fund for Civility, Respect and Understanding, and our first priority was to increase community awareness and to remove the stigma that prevents many people from getting treatment for a mental illness.

This year, I co-sponsored the Mental Health First Aid Higher Education Act, which would provide training to help people identify and respond to signs of mental illness and deal with psychiatric crises. The bill did not pass this year, but I am committed to reintroducing it next session. We also must protect state and federal funding for mental-health services.

There are many other factors that can produce a violent tragedy. But we do know that the availability of certain weapons coupled with mental illness is a recipe for disaster.

Our president said Friday that we must come together and take meaningful action to prevent more tragedies like this -- regardless of politics.
I agree and we must take action now, together, as a national community. We cannot wait.

Barber represents Arizona's 8th Congressional District, succeeding Gabrielle Giffords, who stepped down in January to focus on her recovery. He had served as her district director. Barber was shot in the cheek and leg in the 2011 Tucson-area massacre. This opinion first appeared in The Arizona Republic on December 16.