The Defense Department was shaken a few weeks ago when the Mormon Church came out against the MX missile being built in Utah. It should not have come as a surprise since the Mormons own Utah, and while Americans don't have anything personal against the system, no one seems to want the monster built in his own back yard.

Nevada, the home state of Sen. Paul Laxalt, President Reagan's dearest friend, does not want it either. Sen. Barry Goldwater, one of our strongest defense supporters, has no intention of asking that the system be built in Arizona, particularly since it uses so much water.

So the question is, what place should have the honor of being selected for the MX site?

Texas seems like a good state for the underground missile hiding place, but it presents problems. When you start digging in Texas as deep as our missiles have to be placed, you're bound to strike oil. It would be a very difficult problem for the administration to decide whether the country needs the oil more than it does the nuclear weapons shelter.

New York City would also not be a bad spot, since most of its potholes could be used as dummy missile sites to fool the Soviets. But the difficulty is that if you put the MX system underneath the ground using subway tunnels, vandals would start putting graffiti all over them, and scientists would never be able to prove they had developed a clean nuclear weapon.

New Jersey is a favorite, particularly with senators from the West. Unfortunately everything is being dumped in New Jersey now, and the ground is so full of poisonous wastes that it's doubtful the state's earth could stand another tunnel.

If it weren't for the price of land, California would be a very nice place for the MX system. It's President Reagan's home state, and since he's pressing for it, it would be a wonderful tribute to him to build it underneath his library when he leaves office.

Of course there is the earthquake problem, which cannot be ignored. We could get the missiles all in place, and then a strong quake in Palm Springs might set the damn things off. (For skeptics, I need only remind you a Titan missile in Arkansas was shot out of the ground when a workman dropped a monkey wrench down the hole.)

Forget Rhode Island and Delaware. They are too small to accommodate all the tunnels. Washington, D.C., cannot be considered because the senators and congressmen voting for the system spend too much time there, and refuse to be targets of Soviet retaliation.

Where then? The only answer is Canada, though it's imperative we don't tell the Canadians about it. What we must do is announce we've selected Minnesota as the site for the MX. We start digging right next to the Canadian border. But instead of tunneling south, we tunnel north as far as is necessary to accommodate all the hiding places necessary for the system.

We would have to do the work at night, and carry out the dirt in buckets as they do in prison motion pictures. But if enough workers are involved we could tunnell through by 1985.

Once the tunnels are shored up under Canadian soil, we would give Canada a giant order for wheat. The wheat would be grown on top of the MX system and Prime Minister Trudeau would never be the wiser.

Now, although Canada can't be in on our dirty little secret, it is essential that we leak the location of the MX system to the Russians, so in case of a Soviet nuclear first strike, no one in Minnesota will get hurt.

I know it seems unfair to do something like this when the Canadians did so much for our hostages in Iran. But our national security is at stake and we have to build our tunnels somewhere.

Incidentally, I'm embargoing this column from my papers in Canada, so they'll never find out what we're up to.