Ned Rorem recently helped baritone William Parker win the big $65,000 first prize in the recent Kennedy Center-Rockefeller Foundation Competition for Excellence in the Performance of American Music. And had the baritone who won second prize taken first place instead, his debt to Rorem would have been the same.

Both singers gave complete performances of Rorem's powerful and deeply moving song cycle, "War scenes" (to poems by Walt Whitman) in the final programs that determined the winners. Last Sunday afternoon Paul Callaway filled Washington Cathedral with dramatic visions in sound conjured up in Rorem's equally effective suite of pieces for organ called "A Quaker Reader." It is one of the most impressive new works for organ written in this country in decades.

Back in June 1965, when President Lyndon Johnson let himself be persuaded to hold a day-long festival of the arts at the White House, the Louisville Orchestra was chosen to represent this country's symphony orchestras because of its unequalled track record in commissioning, playing and recording new music. Their conductor, Robert Whitney, elected to play excerpts from Rorem's "Eleven Studies for Eleven Instruments."

Rorem, the most literary of our composers today, recalls two moments from that day in his book, "Music and People." "On my right," he writes, "sat the president of the Indianapolis Symphony, who talked to me all during the music." Some hours later, at a buffet supper, Rorem found the president of the Kansas City Symphony on his right.

When Rorem offered this president the observation that "Virgil Thomson is from your town," the symphony officer came back with, "Ah yes? And what's his line?"

One of the best and one of the last American composers of songs (of the classical, or concert or art song variety -- none of the labels is apt) -- Rorem is coming to town this week tgo play for soprano Phyllis Bryn-Julson in a Library of Congress recital being given on Tuesday, the annual Founder's Day in honor of the late Elizabeth Sprague Coolidge.

In the past, when his songs were first finding their way onto recital programs, Rorem noted that they were often sung by singers who were "vocally dubious." Recently he said of Bryn-Julson, "How wonderful to hear my songs sung by someone who has both a beautiful voice and the brains to go with it!"

Tuesday's concert will offer four cycles of songs: two by Rorem and two by Debussy. Rorem's songs are his cycle, "Women's Voices," written in 1975, to poems that range from lines written by Queen Anne Boleyn in her prison cell, through poems by Emily Dickinson, Elinor Wylie, Christina Rossetti and Anne Bradstreet. From Bradsteet, who lived in the Commonwealth of Massachusetts in the 17th century, Rorem has set the same poem, "To My Dear and Loving Husband," that Leonard Bernstein included in his recent cycle, "Songfest."

A comparison of the two settings of that poem demonstrates again how utterly differently -- yet sometimes with equal success -- two composers will treat the same text. Where Bernstein writes a slow, reflective trio for women's voices, Rorem bursts out with an "exuberant" (his marking) fast song that exults in high-flying lines at the words, "Then while we live, in love let's so persevere that when we live no more, we may live ever."

The second Rorem cycle will be the world premiere of his Nantucket Songs. These 10 completed last May, draw upon poems by Theodore Roethke, William Carlos Williams, Rossetti again, Walter Savage Landor and others. The Debussy cycles will be the "Fetes galantes," and the Mallarme Poems.

Rorem won the 1976 Pulitzer Prize for music with his symphonic score, "Air Music." Asked how it feels to win the Pulitzer, Rorem answered, in his recent book, "An Absolute Gift," that "It's a once-in-a-decade refashioner carrying the decree that bitterness is henceforth unbecoming. Ironically," he added, "it was for an orchestral rather than for a vocal piece. My reputation, such as it is, has always centered around song, or the various tenacles of song: opera, chorus, cantata."

With more than 200 songs published, Rorem says he has three mottos for songwriting: "Use only good poems -- that is, convincing marvels in English of all periods. Write gracefully for the voice -- that is, make the voice as seen on paper have the arched flow which singers like to interpret.

"Use no trick beyond the biggest trick -- that is, since singing is already such artifice, never repeat words arbitrarily, much less ask the voice to groan, shriek, or rasp."

In the same volume, Rorem returns to a subject that is sore to most American composers: "Musically speaking, America is the most vital land in the world, and almost the most abject. Vital, because composition -- music's so-called creative aspect (the first aspect by which the cultural health of a country must be judged) -- has finally matured into model independence. Abject, because the dissemination of this composition, through performance and funding, is slow and painful."

In answering a question that perennially rises to confront composers -- usually in seminar questions -- Rorem writes in his book, "Critical Affairs": "If a composer could state in words what being a composer means, he would no longer need to be a composer. I can't write music and write about music during the same period; the two acts stimulate mutually repellent juices."

On Tuesday night Rorem will act as composer and pianist in music by Rorem and Debussy, worlds in which he has special gifts. The concert will be taped for delayed broadcast at a later date.