It is almost two decades now since the Cuban missile crisis of 1962 forced Americans to look into the abyss of nuclear war and think seriously about what it would mean to themselves and this planet. In the aftermath of that grim encounter, the Cold War eventually faded away and for most of the 1970s there was talk of detente between East and West, and nuclear war was relegated to what seemed its rightful place among the world's unthinkable subjects.

But Iran, Afghanistan, a new Cold War with Moscow and a new hot one in the Gulf, bristling atomic arsenals and new atomic strategies have put talk of nuclear war back into the air again. And whether Americans like it or not, they may soon be forced to look once more into that abyss.

Anybody who wants to understand what he or she may be looking at ought to watch ABC News' special close-up "The Apocalypse Game" at 10 p.m. on Channel 7.

The program is simply first-rate, a blanced, well-informed and understandable treatment of a complicated subject that can be best dealt with when the public and Congress know more about it.

"The Apocalyspse Game" focuses on the central dimma that now confronts President Carter and will continue to confront whoever wins the next election: what to do about the widely acknowledged buildup of increasingly numerous, powerful and accurate Soviet missiles that now, theoretically at least, threaten the security of America's own very sizable missile force?

It is not a simple question. The Soviets have a lot of power and a lot of people worry about it. But the program asks all the right questions. Is the planned U.S. response -- the controversial and enormously expensive MX mobile missile -- the right answer? How will the Russians react to this new U.S. weapon that will threaten their missiles a decade from now? Are we being captured by technology that planners and strategists simply can't resist using?

To remind us that this is not simply some arcane debate among planners in the basement of the Pentagon and the Kremlin, the producers take us on a walk through Boston to show the possible effects of a single atomic blast, and they ride us through the farmland of Nevada, where the MX would be based. Those scenes provide a telling contrast. They somehow catch the difference between the normal lives of Americans and this extraordinary new debate about nuclear war that needs their attention.

The program is neither a sellin job for the Pentagon nor an apology for the Soviets, though it does, to its credit, provide ample interviews with Soviet officials so that Americans get a relatively rare chance to look at this whole question of nuclear war through Soviet eyes as well as through our own.

In short, "The Apocalypse Game" is an honest piece of work that doesn't talk down to the viewers. It says, basically, here are the facts and the arguments, make up your mind, it's important. The persons interviewed on the show were well chosen. There are many views and they are all well expressed. If you're not sure what you feel when it's over, you will have sense the dilemma that now confronts the country and, for the matter, the world -- because the fallout from atomic bombs blows eratically and unpredictably on an ill wind.