Carl T. Rowan promises "an unsentimental view of the Constitution" at the outset of "Searching for Justice: Three American Stories," but that doesn't mean the program isn't moving. Admirable by any standard, but especially so for a locally produced documentary, "Justice" is more than an achievement. It's a proud moment.

Airing at 8 tomorrow night and at 11:30 Friday night on Channel 9, and also being shown on seven other stations owned by the Gannett Broadcasting Group, "Justice" has already made headlines for the interview it contains with Supreme Court Associate Justice Thurgood Marshall, who in the last segment of the show rates modern presidents for their civil rights records. He puts Ronald Reagan at "the bottom . . . down with Hoover," and places Lyndon Johnson at the top.

Johnson appointed Marshall to the court in 1967.

Marshall also recalls how, when he was ill and hospitalized, President Nixon phoned the hospital hopingthe prognosis would be bad so that he could name a new, and more conservative, justice to the court.

What's disappointing about the program is how little of the Marshall interview -- bits of it scattered through the hour -- there is. Much of it has been printed by now, yet seeing the man himself, looking relatively imperturbable and wise, is gratifying. Marshall figured prominently in the third of the three landmark constitutional cases that Rowan examines: Sipuel v. University of Oklahoma, in 1948.

The school did not admit black students, and when finally forced to do so, segregated the lone student behind, literally, a partition in the classroom. Marshall was a young and determined lawyer who helped win the case. Ada Lois Sipuel, then a student striving for admission to law school and now a law professor herself, says that while great strides have been made, "the struggle has to continue."

Lockett v. Ohio, a 1978 case that is the first considered on the program, involved capital punishment, and Rowan talks, in prison, with Sandra Lockett, given the death sentence for her part in a pawnshop robbery-murder even though she was not inside the store when the crime occurred. She is still bitter about the system that put her on death row (from which the court's decision removed her), but so is Gladys Cohen, widow of the pawnbroker, who says she lost her faith when her husband died.

Roe v. Wade, in 1973, was of course the famous abortion decision, still being denounced by those who long to see it reversed. Marshall tells Rowan he has received "all kinds of threats" for voting with the majority. In Dallas, Rowan encounters determined, abusive demonstrators.

One of their leaders, asked about bombings of abortion clinics, says, "I rejoice every time I hear one go up. I think bombing clinics is a legitimate activity. I don't have any problem with it at all." It is frightening to look directly into the face of such virulent fanaticism.

The segment includes Rowan's interview with Norma McCorvey, "Jane Roe" in the original case, in which McCorvey admits that her story about being raped, the basis for her request for an abortion, was false. She was not raped. Nor did she ever have the abortion; her child was given up for adoption at birth. The principle at stake remains unchanged.

Hardly the liveliest of TV communicators, Rowan, with his painstakingly deliberate delivery, is nevertheless an authoritative presence on the program, which was produced by Jeanne Bowers and executive-produced by Sandra Butler-Jones, director of broadcast operations at WUSA. Bowers may have overdone the herald trumpets and the opening tease sequence, and some of the edits are awkward, but those are small complaints.

Many TV observances of the Constitution's bicentennial may leave viewers cold. A constitution is a hard thing to dramatize. Rowan's program, for which he served as managing editor, is consistently engrossing. "You'll never find a better constitution than this one; I know," says Marshall with cheerful reassurance. It's a point driven home by this vital and ambitious hour of television.