"CBS Reports: Arizona, Here We Come," is considerably more than an entertaining recapitulation of the westward flight of middle-class Americans who are "drawn," as correspondent Bill Moyers puts it tonight, "toward a dream which changes with their touch."

It is one of those rare documentaries that manages to illustrate both that paradox of the escapist American dream and the private and political power centers that have been set in motion since World War II to either further or limit the reaches of that vision. It airs at 8 p.m. on Channel 9.

"Arizona" is particularly timely as the implications of a severe and continuing drought in the West become more apparent every day.

And more especially since only this past weekend the Carter administration announced plans to cut funds from the next federal budget for 18 major water projects, one of which, the $1.4 billion Central Arizona Project (CAP), is at the heart of tonight's program.

Although the timing of "Arizona" is only a fortuitous coincidence, viewers who want to understand the implications of the "politics of water" that lie behind the CAP and others like it in the West -- which the White House announcement seems to challenge -- will seldom have a more clear and yet sophisticated television primer on such a complex subject.

The program begins with one of those uncomfortable mirror images of the American buying public at bay, standing in the desert heat awash in singing commercials delivered with the quasi-religious and patriotic fervor we associate with half-time shows from Texas football.

But having glimpsed ourselves, correspondent Moyers moves us behind the scenes to meet the land salesmen, contractors, state land officials, car dealers, real estate lawyers -- and finally the officials and workers of the huge Central Arizona Project itself --all bent on diverting the water that will keep this business cycle in motion.

Only recently have we begun to understand the impact of the western migration in this country. The demand for electrical energy, which depends on water in one process or another, has increased geometrically in the West. And water is in short supply there, even in the best of years.

As home builders have moved to Phoenix and Tucson -- the focus of tonight's inquiry -- they have stretched to the limit what we have finally understood to be finite supplies of ground and river waters.

The pressure for more, from anywhere, has greatly enhanced the power of the bureaucracies within the Interior and Agriculture Departments controlling so much of that vast region.

In turn, western congressional delegations who, at budget time, champion those causes for a burgeoning voter population, have gained in national power; meanwhile surrounding states, jealous of their own shrinking resources, have mounted increased opposition.

This is the core of the dilemma and it is here that "Arizona, Here We Come," comes to grips with the paradox of the limits of the American dream.

Although Moyers is clearly on the side of teh vanishing West and the victims of civilization's encroachment --the fragile environment -- he is shrewd enough to understand that the paradox lies within all of us, as a nation and as an ever-increasing group of escapists who want it both ways.

Moyers wrote tonight's documentary with producer-director Janet Roach. It is three-dimensional TV journalism, the kind viewers learned to expect from Moyers during his years in public television.

With this program, Moyers hits his stride at CBS. In doing so, he illuminates brilliantly what is probably behind President Carter's decision -- sure to be fought hard by Arizonans and other Westerners -- to cut back waste and environmental threats despite what may already be an irreversible process.