MERE MENTION OF the Crisis Relocation Plan is enough to bring down the house at almost any gathering of Americans. The House of Representatives, however, despite its name, is different.

Last week it voted, 240 to 163, against cutting funds for creating a countrywide traffic jam, which is what CRP proposes as a "strategic deterrent capability" in the nuclear war-game calculations.

There were some chuckles during the hour- long debate, particularly when Rep. Edward J. Markey (D-Mass.) -- author of an amendment that would reduce CRP's purse to a level that even the hawks on the Senate Armed Services Committee thought sensible -- stood before a chart and revealed the marvels of the "Car-Trench Plan" offered by the Federal Emergency Management Agency (FEMA), for those who are caught between "host" and "guest" status as the missiles begin to fly.

After explaining how all that is needed for salvation is four sandbags, 50 feet of strong twine, two long-handled pointed shovels, 11 bedsheets and two day-laborers (the scheme requires eight hours to dig the car's grave), young Markey said, "But if the distance between your front wheels is not 44 inches, as prescribed in the manual, this plan is not for you."

There were many appreciative chuckles from the liberal Democrats, and the Republican and southern Democratic managers of the bill looked apprehensive. Middle-aged men in seersucker suits kept rising to hint that Markey was against providing warning systems for schoolchildren who are about to be drowned in a flood or whirled away by a cyclone.

Proponents were sheltering behind the schoolchildren and other victims of natural disaster. And, of course, the psychology of the Reagan administration has been from the first that nuclear warfare is no big deal, offering a difference in degree, not in kind, from natural catastrophes.

Markey and his company protested in vain that the fund cut would not be taken away from people needing sirens, blankets or hot meals in the event of fire or flood.

What carried the day in the end, against all common sense, was what Rep. Barney Frank (D-Mass.) called "Brezhnev envy." The argument for civil defense comes down to the fact that the Russians are doing it.

"Just because the Russians act stupid is no reason for us to act stupid as well," said Frank. "It isn't evil, it isn't obscene, it's silly," he told the House.

Frank comes from Brookline, which is slated for evacuation to Laconia, N.H. The Brookline selectmen, who think that CRP is a scream, wrote to the selectmen in Laconia to ask if they could come. The Granite Staters wrote back that they would love to see their guests "in the off-season."

The friends of CRP admitted they had no idea how the Soviet civil defense plan works. One of them, Rep. Donald Mitchell (R-N.Y.), said he really didn't know whether it was good or bad, only that the Soviets think it's good, which apparently makes them more philosophical about the advent of nuclear war.

"All we want to do," he said, with a collapse of logic that was the hallmark of the debate, "is to provide a system as good or as bad as what the Soviets give their people."

"If," asked Rep. Tom Downey (D-N.Y.) at a later point in the debate, "we saw the Soviets providing their population with lead suits, would people in the House start talking about 'a lead-suit gap'?"

Undoubtedly.

But the House was beyond derision.

Rep. Ken Kramer (R-Col.) said, "What this country needs is the ability to offset the plan for the Soviet evacuation of their cities."

It was never clear exactly why the emptying of our cities to the countryside, with sufficient notice from the Kremlin, would cause the Soviets to quake in their boots and pull back their finger from the button. Presumably, if they thought that with CRP we would suffer only 15 million casualties, instead of the 150 million without CRP, they would not think nuclear war was worth the trouble.

Mitchell repeatedly asked Markey what he would advise his friends and family to do as Doomsday dawned.

As a matter of fact, Markey has a prescription. It is to prevent nuclear warfare. He is the sponsor of a resolution for a nuclear freeze on both sides. It will come up on the floor next week. Its prospects are dim.

The House is now on record as saying that nuclear war is survivable.

It is a discouraging conclusion, although not altogether unexpected from a body that voted funds for the MX missile, which also has no place to hide.

The only thing the House has done so far in the defense-budget debate is to turn down chemical warfare. It says an awful lot about where we are that we are expected to be grateful for that.