My friend Mike was a sailor on a “boomer” – a ballistic nuclear submarine. After spending most of his youth underwater on a reactor powered vessel crammed with nuclear warheads he likes to joke that he still glows in the dark.

“So what was the launch depth again?” I asked him one night.

“I can neither confirm or deny that information,” Mike said.

“C’mon. I’m not a Russian spy. Tell me.”

Mike looked at me over his glasses. “That information’s classified forever.”

“One day it’ll slip out. You’ll tell me.”

My trying to get classified information out of Mike is a long running gag between us. When we talk about his days as a submariner he usually regales me with stories about ship fires, practical jokes, emergency ballast blows and the craziness of living with a bunch of guys trapped seven leagues under the sea.

“So,” I said. “Would you have pushed the button?”

“I was just a radioman,” Mike said. “I only passed along the EAM – the emergency action message. That would have been the order to fire. After the captain and the XO confirmed it and some things got done the weapons officer would have launched. And it’s not a button – the firing mechanism is the handle of an old Colt .45 attached to the computer by a cable. He would literally pull the trigger.”

“But what happens if the crew goes nuts all at once?” I said. “If the captain pulls an Ahab? Could they launch the missiles?”

“No,” Mike says. “The codes to launch the missiles are not on the ship. They get transmitted with the EAM. No way to launch them without it. Besides there’s something called PALS – the ‘Permissive Action Link System.’ It’s a whole bunch of software and hardware safeties built into the warhead. Even if we managed a shoot a missile off the warhead wouldn’t arm. Trust me, they’ve thought of everything.”

“Good to know.”

“The British don’t have that, though,” Mike said. “Their sub captains can launch whenever they want.”

“That’s crazy.”

“We offered them the PALS system but they turned it down,” Mike said. “They were afraid if London was wiped out there’d be no way to transmit the launch codes. So their system is very different. When a new Prime Minister takes office he or she writes four handwritten letters giving instructions to the captains of their four subs what to do if England is destroyed. They’re bolted in a safe within a safe and only the captain has the key.”

“Letters?” I said. “Friggin letters? That’s it?”

“The letter of last resort they call it,” Mike said. “If the British captain thinks there’s been a nuclear attack he’ll run though a checklist. Is the the BBC still broadcasting over the radio? Can he get hold of the fleet? Stuff like that.”

“And then he opens the safe?”

“Yep, and he does what the letter says,” Mike said. “They are usually given four options – retaliate, not retaliate, the Captain may use his discretion or put his sub under the command of another country – Australia or the U.S. would be my guess.”

“I’d hate to write that letter,” I said.

“You take the job,” Mike said. “You take on the burdens. Besides, no one but the PM ever sees the letters. They’re destroyed when he or she leaves office.”

Back in the early Eighties I was a big nuclear disarmament kind of guy. If you’re old enough to remember those days, TV movies like The Day After has us convinced WWIII was around the corner. I eventually did a school project about nuclear weapons and won a prize for it. Instead of talking about scrapping nukes, however, I focused on their destructive potential. I set up a map of our area and explained what would’ve happened if a one-megaton airburst exploded over Manhattan. The results wouldn’t have been pretty. I left it to the audience to decide if they wanted to have that destructive capability at mankind’s disposal. Personally, I wanted all of those weapons scrapped.

Then I got older and wiser. Personal experience showed me that some people only understand force. I’ve dealt with enough psychopaths to know that they won’t attack unless they think they can get away with it. That’s kind of what’s going on with nukes but on steroids. Mutually assured destruction – MAD – is the name of the game. You might get me but I sure as hell will hit you back. It’s an ugly and deranged philosophy but so far its worked.

Of course I want to see nuclear weapons go the way of the dodo bird but we’re not there as a species yet. In the meantime, I don’t want my country open to attack. So I’m more of a “reduction” kind of guy now. I’m all for shrinking our arsenal, combating proliferation and keeping fissile materials out of the hands of lunatics. But I want those weapons to work as advertised so an adversary doesn’t think were vulnerable. I’m all for making sure those missiles fly.

Driving home from my night with Mike I thought about being the newly elected Prime Minster of Great Britain. What would I put in my letter of last resort? As I thought about it I realized that if some poor sub captain was reading my letter everything had gone to shit. Deterrence hadn’t worked and MAD turned out to be a lie. The whole purpose of having these terrible weapons had been for naught. Would I still order the deaths of millions of people from the grave? Suddenly being older didn’t make me wiser.

I thought about the Russian version of my daughter being incinerated in a nuclear blast or dying from radiation positioning. Disgusting. Chilling. I don’t think I could do that. Maybe I’d tell the captain not to fire and call it a day. Find some safe haven and start making babies. Pass the buck to Australia.

But what if my enemies knew I was unwilling to fire? After I got elected the bad guys would have teams of people psychoanalyzing me. Perhaps I’d give off hints and they’d figure out I wasn’t up for wiping out their country – that I wanted my last posthumous act to be one of mercy. To turn the other cheek. Then they might be tempted to attack! And I was elected to keep my country safe, not indulge my personal sense of morality. So is the rational thing to be irrational? To let the enemy know that yes, despite my country being incinerated I’d still kill your children? In that case I’d have to tell the captain to let let slip the dogs of war. I hope there’s room service in hell.

As I pulled into my driveway my head was hurting from my little thought experiment. Not for the first time I’m grateful I’m not in politics. I’d never want to be put in that terrible position. As the missiles were raining down I’d probably just start crying. But we all have skin in this game, people. You may not ever be faced with such a terrible decision but you get to pick the man or woman who might have to. What kind of person should have that power? Hopefully a person who has children and grandchildren. A person who can navigate the rational and irrational with a clear head and humanity.

I think the British actually have a good system. Their leader has to put pen to paper and decide in advance what they want their last act as a human being to be. They have to think about the unthinkable in advance and I’m sure they struggle with it mightily. The American command and control system, as my friend Mike pointed out, is quite different but, in a sense, it is the same.

When you vote for President you are signing your own letter of last resort. Think long and hard about it.