The thing to remember about "Eleanor and Franklin" is that it is a pageant.

Subtitled "The White House Years," the 3-hour special will be aired Sunday from 8 to 11 p.m. on Channel 7.

This is the second part of the FDR story, drawn from Joseph Lash's Pulitzer-winning biography of the same name and starring Jane Alexander and Edward Herrmann, whose portrayal of Roosevelt's early life was "the most-honored television special of 1975-76."

I quote the press release because this is one of the things about pageants: They require reverence. Riding on the shoulders of historical fact, relying on our knowledge of famous events for their dramatic effects, pageants claim immunity from serious judgment either as history or as art.

As a pageant this is a great work. Though the first segments are a bit overstuffed with exposition ("It's 28 years since we were here last . . ." "When I spoke of the Good Neighbor policy this afternoon . . ."), we eventually get a superb balance of public happenings and private encounters. We get a very sense of the human cost of greatness.

Jane Alexander's Eleanor, aided by special dental makeup, is so controlled and contained that the slightest flicker of emotion wrenches the viewer, and on the rare occasions when she lets go - after a baby's death in flashback and after FDR's death - the impact is electrifying.

Herrmann, hampered by the nature of his role, does not so much act as reenact. He never does seem quite comfortable. But the mannerisms and the speech, especially the Pearl Harbor address, are uncanny.

For anyone who knew the Roosevelt from the newsreels and the radio and the papers and magazines, "Eleanor and Franklin" will have the eerie not-quite-rightness of a wax museum. But one gets over this. The show builds, gathering strength, until in the last scene all the hinted tensions, all the anguish of neglected love, all the poignancy of life passed by, of chances missed, all the pent feelings pour out in one magnificent moment.

I do wish the picture did not suggest that Eleanor's useful life ended with Franklin's death. In fact, her best years were still to come.

If "Eleanor and Franklin" is a powerful and moving pageant, as a film it is not so fortunate. The camera work is worse than pedestrian. There are virtually no closeups. Everything is middle-distance two-shots: we follow dialogues like spectators at a tennis match.

As for cliches - in a pageant they become emblems, a kind of visual shorthand. We get the one-legged soldier in the hospital, the sad stroll in a military cemetery, the montage of headlines. Now really, I thought Mel Brooks had finally put to death that crashing cliche of the bundle of papers being thrown off the truck, newsboy cutting string, holding up paper with black headline for us to read. But there it is again.

Old newsreels are used intelligently to sketch events of World War II. Not so successful are fake newsrells of Eleanor's activities. Why is it that we can spot actors instantly when they're trying to look real?

It is beyond my powers to imagine how these people and events will come across to anyone who didn't already know them - the devoted Missy LeHand (touching portrayed by the underrated Priscilla Pointer), Louis Howe, Harry Hopkins and the rest. We only glimpse them here, and unless one already understood their significance in the Roosevelt story, I can't suppose they would mean very much.

Doubtless this show, like its predecessor, will be "most-honored," because nothing makes us go all solemn as much as high kitsch. But I don't think it will change anyone's life.