I was a country boy. When I was growing up, there was a shotgun in the house. Dad shot clay pigeons for sport. I fired it once myself, with his assistance. Had to wear ear protectors. When you pull the trigger, a shotgun punches you hard in the shoulder. It almost knocked me over.

Decades later I fired a handgun at a shooting range in Las Vegas. At first I didn't even want to hold it. It represented a level of fearsome responsibility I didn't want to bear for even a few minutes. Once in your hand, a gun seems heavier and somehow more real than you anticipated. You face the target (in this case, a fullsize photocopy of Osama bin Laden). Pull the trigger and your hand kicks upwards, the blast 20 times louder than the imaginary one you had been mentally preparing yourself for. Adrenaline sears through you. You tingle. It's exciting. Once you've fired a gun, it's easier to understand people who don't want to give theirs up.

And the US is not Britain. There are places where you can drive in one direction for several hours without seeing a soul. On honeymoon, I recall looking out of the car window, somewhere in the middle of nowhere, and seeing a tiny house all on its own. If I lived there alone, I figured, I'd want a gun.

Anyway. None of those feelings, real as they are, are anywhere near as potent as the sensation I had this weekend.

The last time I'd experienced something similar was in November, looking at pictures of a BBC video editor clutching the body of his son, killed during a rocket attack on Gaza. I mention this backdrop not to make any political point. It was a story that hit me, and hit me hard. The man's son was still a baby.

"What did my son do to die like this?" the man said. "What was his mistake? He is 11 months old. What did he do?"

There was a photo of the boy when he was alive. Wide brown eyes. Smiling. He looked like my own son. So much like my own son. It built inside me, a wave of nausea and dread, and I couldn't stand it. I shut the webpage. There was nothing I could do. I was helpless. It hurt.

Now it's December. Newtown. Twenty-six bodies, and what can you say? Again, some stories hit you so hard that after the initial mesmerising horror, your secondary instinct is to protect yourself, to shut the mind down, halt the imagination before it conjures the details that lurk between the brisk lines of the news reports. The sights, the sounds, the terror, the grief. I simply cannot bear to place myself in the shoes of those parents. To be racing for the school, feeling unreal, light, weightless, powered by gut fear alone. To stand and wait, and wait, and wait. To hear your child is dead.

I don't have it in me.

The news displays the faces of the children and I have to look away. That feeling, still relatively new to me, becomes overwhelming. The basic parental urge to protect. They are other people's children. Faces in photographs. Gone now. But still: the urge to protect. And I can't. I'm helpless. It hurts.

Not so long ago when other people wrote words like that I would roll my eyes at their soppy bullshit. Their gauche sentiment. I miss reacting like that. I knew nothing; I was an idiot with nothing at stake. But still. I miss the warmth of that bubble, the cosiness of that protective sneer. It's cold outside.

Over the past few days a fair few people have retweeted an excerpt from a show I made in 2009 in which a psychologist urged news organisations not to sensationalise their coverage of massacres, on the basis that this had the potential to inspire further tragedies. That may well be true, and there's no harm pursuing it. But the best way to improve media coverage of massacres is to prevent massacres. And try as I might, I can't think of a better way to prevent massacres than reducing the number of guns in circulation.

Twenty children shot at close range with an assault rifle. You could argue that the choice of weapon is irrelevant; that a truly unhinged individual would still find the means to kill. Maybe that's true; I don't know. All I know is that 20 children were shot at close range with an assault rifle, and that only a lunatic nation wouldn't try everything it could think of to make that less likely to happen again.

America, don't be helpless. Look at the faces. Feel how much it hurts. Try to stop it happening again.