There are no words for this.

A gunman opened fire Friday at Sandy Hook Elementary School in Newtown, Conn., killing 20 children and six adults. Twenty children, all 6 and 7 years old.

There should be no words for this.

But we know how this goes.

I hate that we know how this goes.

I hate that we can’t just say, “Oh God,” and “Oh God, horrible, horrible.”

I hate that we have to say, “Not again.”

I hate that we realize this. “Now it starts,” we say, “and then a few days or weeks or months from now after we have exhausted our grief and indignation, nothing will change.”

I hate that there is a familiar outline to all this, that we know what comes next. Next, the papers will be plastered with pictures of the man who walked into the school and opened fire.

I hate that we will pore over his life and habits and personal quirks. I hate that books will be written about him and that we will know his name. I don’t want to know his name. I don’t want him to draw the bizarre adulation drawn by anyone whose name is in headlines often enough. I want him to sink out of existence, miserably forgotten.

I hate that we will use this tragedy to show how Right We Were. That people will go on television insisting that they know What Caused This, and that it was Video Games or Our Culture of Non-Empathy, or Atheists, or Our Loss of Faith (all actual suggestions I have heard) or that there is one specific hobbyhorse that can be pinpointed.

I hate that we have a template for tragedy that should have no template.

Already, the usual arguments have started. I hate that there is anything usual about this, that when we speak of unspeakable massacres we have to specify which one.

They are always different. Columbine. Virginia Tech. Fort Hood. Tucson. Aurora. This time was different. This time there were young children, terrified, being told by police officers to close their eyes.

But there’s a ritual to it now.

The name of the place where this awful thing occurred becomes more than a name. It becomes a horrible shorthand for the day we were forced to stop believing that such a thing was impossible. For that first wrench in the gut. For the recriminations and the arguments.

The date on the calendar takes on a new anxiety. We have a miserable anniversary to remember. More candles to light, more thoughts to send, more prayers to say. Our grief is consistent.

Why do we do this every time? Is this what we feel we have to do, our practiced answer to the unanswerable? There are no words — no good words, but we say them because these are the words we always say.

This will be the only thing we talk about for a very long time.

“Our hearts are broken today,” President Barack Obama said. “As a country, we have been through this too many times.

Whether it is an elementary school in Newtown, or a shopping mall in Oregon, or a temple in Wisconsin, or a movie theater in Aurora, or a street corner in Chicago, these neighborhoods are our neighborhoods and these children are our children. And we’re going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics.”

But how?

I know what the script demands. But I hate that something too awful for words has a script.

No single law stops this. No one policy fixes this. Evil persists. Some crimes cannot be prevented. But that does not mean there is nothing we can do.

The next time we say “Not again,” I want it to be a promise.

Alexandra Petri writes the ComPost, a lighter take on the news and issues of the day, and she contributes to The Washington Post editorial page.