It’s a Tuesday in April and the lockdown drill is at 12:45 p.m. The rest of the faculty and I know it is coming — the students in my math classroom, and the rest of the students in the high school, including my son, do not.

Over the intercom the dean of students announces we are in lockdown. I shut and lock the wooden door and pull down the shade over the door’s three portal windows. The shades were installed on all classroom doors a few years ago as a part of the new-and-improved lockdown procedure. The back wall of my room is half filled with tall rectangular windows. The shades are already down. We can see outside but no one can see in. Supposedly, we can push the windows out of the frame if we need to escape the building that way. I imagine trying to do so. My students whisper nervous jokes as they huddle into one corner of my classroom, next to a white board filled with equations, a mix of their handwriting and mine. I want to remind them this is just a drill and then tell them maybe someday this will seem as campy and barbaric as the hide-under-your-desk-an-atomic-bomb-is-coming drills of the 1950s and that they’ll be OK, but I don’t say anything. I keep quiet because I want them all to know this is serious. I want them to know that this regimented, practiced, and uniquely American horror is serious. Of course, they know this already.

I wonder where my son is. Is he in the physics lab with one of my colleagues? Is he in the cafeteria, one of a hundred other students in that wide open space? Is he across the street in the gym? Is he afraid? My son is in the 11th grade. He shaves and drives and he weighs as much as I do, but he’s still a kid.

I imagine hearing rapid-fire gunshots. I can’t help it. I’m a daydreamer, a purposeful one when I’m writing fiction. In my day-to-day, I’m a planner and a considerer of worst-case scenarios. Many schools are now encouraging their faculties to use their best judgement within the lockdown protocol as to whether we remain huddled in the classroom or lead students out of the building and to safety. I imagine doing the latter and then running back inside the school to look for my son, but I don’t allow myself to follow that particular scenario all the way through to various and inevitable ends. As an adult I’ve learned to cope and pull the plug on the worst what-ifs before my mind takes me to a place from which I can’t return.

My middle-school-aged daughter struggles with anxiety and has yet to build her personalized coping mechanisms. She’s working on it. In the meantime, this past week someone drew a swastika in the boys bathroom (the school sent the parents an e-mail about the incident). A month or so ago, the power in her school went out for about 30 seconds, and my daughter instantly assumed that someone with an assault weapon was responsible.

All of this isn’t to say that I work and live in daily fear of the school shooter. School shootings represent a fraction of the overall gun violence in the United States. What keeps me up at night is our nation’s continued and burgeoning lack of rationality in response to mass shootings.

I fear the loud minority (according to a recent Quinnipiac poll, 67 percent of Americans favor a federal assault weapon ban) who wage a holy war to keep the weapons of war in bloody hands. I fear the angry white man recently suspended from Twitter, the one with the AK shooting an effigy of a teenage mass-shooting survivor. I fear the legion of NRA-purchased politicians, pundits, and social media hawks who use the language of religious worshipers when they fervently speak of assault rifle ownership as a God given right, and when its most odious mouthpiece (Ted Nugent) says that the teenage Parkland shooting survivors asking for and working toward sensible gun control have no souls. I fear the profiteers and willing political partners of these zealots, who I assume do know better but simply don’t care. Thoughts and prayers, indeed.

For too many of our citizens, Christianity has become entwined with the ecstatic worship of the gun and violence. For the adherents, there is no compassion, no love thy neighbor, no peace, no reason, and God only helps those who arm themselves. How else to explain their ignoring the “well regulated’’ part of their 11th commandment, the Second Amendment? How else to explain the refusal to allow the CDC to study the effects of gun violence in the Unites States? How else to explain the willful blindness to statistics? America wildly outstrips the rest of the world in the number of mass shootings and gun fatalities. There’s a linear or one-to-one relationship to state statistics of gun-ownership to gun deaths per capita. There’s a math teacher joke to be made about our appalling national lack in regard to understanding the numbers, but none of this is funny. How else to explain the willful blindness to common sense as a killer with an assault weapon has the ability to murder a large number of people in a matter of minutes, while one with a knife/pistol/rifle cannot come close to achieving the same amount of damage? How else to explain the indifference to the wages of violence to be forever paid by its victims, survivors, and witnesses? Two hundred thousand students have had school shootings on their campuses since Columbine, in April 1999. How else to explain the depths so many of our citizens have sunk to in regard to their ugly reaction to the unfathomably brave Parkland mass-shooting survivors?

How does one attempt rational dialogue with zealots? The gun is an article, a sacrament of their faith, and they’ll be damned if anyone dare say otherwise.

I and my fellow teachers and the students — your children — will continue the drills. We’re reluctant participants in the sacred rituals and reenactments of our 21st- century, uniquely American tragedies. And as we hope to stave off the next chapter of our new history of violence, our greatest fear is that nothing will change.

Paul Tremblay is a novelist and math teacher. His forthcoming novel “The Cabin at the End of the World’’ will be published in June.