THE SCREEN: 'FOLLWOING THE FUHRER'

TWENTY-FIVE years ago Erwin Leiser, the German-born Swedish film maker, put together a documentary feature he called ''Mein Kampf,'' a comprehensive history of the Third Reich composed of clips from old newsreels and footage obtained from both Allied and German sources. Though much of the material wasn't especially new, ''Mein Kampf'' was an effective summation of the Nazi era as recorded on film.

Now, as a kind of supplement to ''Mein Kampf,'' Mr. Leiser has made ''Following the Fuhrer,'' which opens today at the Film Forum. ''Following the Fuhrer'' mixes documentary footage with a half-dozen fictional sketches that are intended, in Mr. Leiser's words, to allow us to ''experience the thoughts'' of the largely characterless people seen en masse in documentaries and newsreels and as idealizations in Nazi propaganda movies.

The result is a not-great hybrid. The fictional sketches, written by Oliver Storz and directed by Eberhard Itzenplitz, feature some impressive German actors, including Armin Mueller-Stahl and Gottfried John. However, the sketches are mostly as perfunctory as the dramatized vignettes contained in Army training films. They're far more cautionary than dramatic.

Mr. John, the memorable Reinhold in Rainer Werner Fassbinder's ''Berlin Alexanderplatz,'' plays an oafish ''weekend'' Nazi, who spends his days off from his job demonstrating outside Jewish-owned stores. In another sketch, Mr. Mueller-Stahl (''Lola,'' ''Colonel Redl,'' among others) appears as a conspicuously patrician, conscience-stricken engineer who drives the trains that carry Jews to the death camps. (For a far more insightful portrait of a man in such a position, see Claude Lanzmann's ''Shoah.'') Only fiction of the highest order could compete with the still-astonishing impact of the film's documentary footage, and this Mr. Storz and Mr. Itzenplitz do not deliver. The sketches simply aren't good enough to do anything except interfere with the dramatic flow of the fact footage that contains them.

Included in the unusual documentary material I've never seen before is a giant Christmas pageant, staged by and for railroad workers, in which the re-enactment of the Nativity marks only the small beginning of a story that has its climax in the triumph of National Socialism.

Stepping Along FOLLOWING THE FUHRER, a film by Erwin Leiser; dramatic sequences directed by Eberhard Itzenplitz; written (German with English subtitles) by Oliver Storz; photography by Gerard Vandenberg and Jochen Radermacher; a production of EML-FILM, Munich with ZDF. At Film Forum 1, 57 Watts Street. Running time: 90 minutes. This film has no rating. MargaLisi Mangold ArthurFelix von Manteuffel BrockeGottfried John DeschlerFrank Strecker DurrWalter Schultheiss KrammHorst Bollmann Mrs. KrammIlsemarie Schnering Elisabeth KurzKarin Baal KurzArmin Mueller-Stahl Ellen KurzTherese Lohner