"How can a nation," narrator Ben Wattenberg asks early on tonight, "that believes it hasn't done anything right in the recent past even consider that it can do anything right, or bold, or creative in the immediate future."

Well, for one thing, it can watch Ben Wattenberg at 9 on Channel 26 give a spirited and amusing - and sometimes glib - defense of American big business. The program is the first of six monthly programs titled "In Search of the Real America" that he has helped design to brag up major institutions in the American system.

"There's No Business Like Big Business," tonight's premiere, should prove to be a real curiosity for both public and commercial TV audiences, coming across as basically optimistic about the past and future of a key factor in our often-criticized "way of life."

A few years back, a series like this could have blown public TV out of the tub. Liberals would have excoriated public broadcasters for seemingly knuckling under to the Nixn administration's drive against liberal public affairs shows.

In today's atmosphere, the most that will probably result from this refreshing, if Pollyannaish look at things-as-they-are, will be a demand for equal time from the liberal left that seems to be Wattenberg's target.

The series is the brainchild of a couple of producers who worked the conservative side of "The Advocates" debate show out of WGBH-TV in Boston a few years back.

They received Wattenberg's permission to adopt his book, "The Real America," into a series which the Corporation for Public Broadcasting and several big corporations and foundations have funded for about $600,000.

"This isn't a glorification of business or anything like that," executive producer Austin Hoyt insisted yesterday. "It's a way of defleating rhetoric and a kind of an experiment for us in 'good news journalism.'"

It is that. Wattenberg, who comes across well on the tube, confines tonight's defense of big business to three charges - that it stifles competition, manipulates taste and either ignores or contends with public policy and the need for long-range central planning. He ignores excess profits or the problems of federal regulation.

His arguments are buttressed by James Michaels, editor for Forbes magazine, Irving Kristol of The Public Interest and Bruce Scott of Harvard. The omnipresent John Kenneth Galbraith appears for a rebuttal that, it must be said, Wattenberg never quite permits to take shape.

Future programs will deal with liberal criticisms of "meaningless work"; U.S. "plundering" of Third World resources, and the implications of American foreign policy and defense spending.

This is a series that should be welcomed to public TV, which has been treading a middle line for so long in the wake of the Nixon days that it has forgotten how to provoke emotion from either side of the political spectrum.