Katie Couric's Notebook: Tragedy in Tucson

Hello everyone. Katie is on assignment in Tucson. I'm Seth Doane.

The shopping center where tragedy erupted Saturday joins a long list of places seared into our memories because of senseless gun violence among them: Columbine High School, Virginia Tech, and Fort Hood.

Once again, the story seems all too familiar - someone who had raised red flags is accused of doing the unthinkable.

The suspect this time had been suspended by his community college last fall and told to get a mental health evaluation. Still, he was able to walk into a gun shop and buy a semi-automatic weapon.

The attack on one of their own has some members of Congress, mostly Democrats, talking about re-starting the debate on gun control. Others are asking for more protection when they attend public events. They insist voters would still have access, but next time, maybe with a few cops on hand to make sure their town doesn't get a place next to Tucson ... on a list that's only growing longer.

I'm Seth Doane, CBS News.