Plus it was a knuckleball of a program, with Hailstork’s austerely dovetailed twin homage to John F. Kennedy and poet Robert Frost situated between Duke Ellington’s sumptuous 1950 scene piece “Harlem” and John Adams’s 1985 masterwork “Harmonielehre.”

But in person — at least on the first run of a program that repeats Saturday — the evening was lacking vital crackle. Thursday nights are Thursday nights, sure. And orchestras under the guidance of guest conductors can often register the audible discomfort of a first date. But along with the program’s trio of unlikely repertoire, the orchestra was also grappling with a uncharacteristic hesitancy.

In the Ellington, we heard an example of the orchestra admirably if perilously venturing outside its comfort zone. Lately a model of careful control and precisely realized detail, this NSO seldom has reason (or opportunity) to swing, and the bright lights, bustling pace and effortless cosmopolitan elegance of “Harlem” suffered slightly from a stiffness in the joints.

Despite some thrilling honey-in-the-horn ornamentals across the brass section — particularly the limber trumpets of Josh Kauffman (a player with the U.S. Army Blues) and Brian MacDonald (of the U.S. Air Force’s Airmen of Note) — the “band” seemed to trudge. This despite percussionist Erin Dowrey’s reliably solid place in the pocket at the trap kit.

Ellington’s gleaming portrait of a living, breathing city too often felt mottled into watercolors, and although Edusei worked hard to emulsify a consistent vibe, his results were distractingly mixed — here too slick, there too slack. A lively percussion solo by James Ritchie delivered a closing thrill, and taken together, “Harlem” was still beautiful: rich, generous, unabashed in its tenderness. But Edusei’s hand didn’t always effectively showcase Ellington’s.

At the core of the evening was the program’s centerpiece, Hailstork’s “JFK: The Last Speech,” an NSO co-commission premiered at the Colorado Music Festival in July. And at the core of “The Last Speech” is Kennedy’s final address, delivered at Amherst College in October 1963, less than a month before his assassination.

The story around the speech is spicy enough that it might have warranted some explanation from the stage, but it was confined to the digital program. So here’s the short version.

Two years after Frost famously read “The Gift Outright” at Kennedy’s 1960 inauguration, the budding friendship between the two men would fracture.

Frost, as a consultant for the Library of Congress, accepted the invitation of Arizona congressman Stewart Udall to join a trip to the Soviet Union to lead discussions with writers and artists toward “constructive forms of rivalry between our two countries.” But the poet had greater ambitions.

The trip resulted in a bedside visit to Frost from none other than Soviet leader Nikita Khrushchev (Frost had a fever) and a long conversation. To Frost, this unlikely exchange signaled the advance of ideals about peace and prosperity between rival world powers. To Udall, who recalled the incident for the Los Angeles Times in 1988, it allowed Khrushchev to employ “a Russian version of poetry-and-power to push his program of political reform.”

Upon return, an exhausted Frost inexplicably tossed reporters a devastating “quote” (which was actually just a turn of phrase he liked): Khrushchev, he said, “thought that we’re too liberal to fight — he thinks we will sit on one hand and then the other.”

“I was appalled,” Udall wrote. “Frost had misrepresented Khrushchev’s position … and embarrassed his friend, the President.”

The next morning, The Washington Post’s headline sealed the poet’s blunder into history (“Frost Says Khrushchev Sees U.S. as Too Liberal to Defend Itself”) and sunk the men’s friendship. Kennedy stopped replying to Frost’s wires, sent no flowers to a hospitalized Frost in December 1962, and wouldn’t mention him until the following October, in a speech at Amherst to dedicate a new library in the poet’s name.

That backstory lends more than a bit of emotional heft and conceptual reverb to the divergent roads in the yellow wood of Frost’s poetry, which too often gets flattened into mere landscape. The speech — portions of which were narrated with stentorian distance by Rashad — is a treatise on the importance of artists in the shaping of American society, but it’s also a eulogy tinted with a deeply human hue of hurt and regret.

Perhaps it was this dimension of heartbreak and human connection that was missing from the performance of this carefully composed, artfully balanced piece of music, which on Thursday felt low on blood. The music’s gentle alternation between the voices of Rashad and Burton — whose bright and lithe-voiced soprano was a delight throughout — seemed neither in service of the gritty grace of Kennedy or Frost. It had, instead, the under-glass feeling of a museum vitrine.

Some of Hailstork’s strongest work takes the form of tribute. His operatic and choral works have examined the lives of historic Black figures, including Crispus Attucks, abolitionist John P. Parker and the poet Paul Laurence Dunbar. He has also adapted presidential texts in the past, to bracing effect: A recent performance by the Cathedral Choral Society and Heritage Signature Chorale of his 1985 piece “Done Made My Vow” incorporated lines from President Barack Obama’s speeches.

And while there were lovely moments throughout its 28-or-so minutes — the opening assembly of harp and flute atop a scrim of ascendant strings was a sublime start — missing was the darkness and depth of Frost’s forest, and the poetry and power of Kennedy’s vision. Burton’s voice sometimes felt unsupported by music that grew diffuse and uncertain. The sound felt starved of its story.

Things came rushing back to life with the opening E-minor browbeating of John Adams’s “Harmonielehre.”

Titled after Arnold Schoenberg’s 1911 text on music theory, the piece was intended by Adams to both break a stubborn stretch of writer’s block and concoct a unified theory of his compositional sense of self. And while its three movements are strewn with stray fragments of Sibelius, Debussy, Mahler, Schoenberg and Wagner, the alloy of Adams’s music gets its particular shine from his masterful negotiation of minimalist impulse and maximalist indulgence.

Bending his body into a tense crescent, Edusei crafted fabulous textures from the strings, expertly managing the piece’s swirling subcurrents — there’s always something coursing below Adams’s shiny surfaces. Towering shocks of brass made for big thrills in the second movement, and pristine shimmers illuminated the dreamlike third, which builds to what Adams has called “a buffalo herd in E flat major.”

Here, too, the NSO seemed to be paddling in unfamiliar waters. We don’t often hear this orchestra work through the rhythmic spin cycles of minimalists like Philip Glass or Steve Reich. And in the rough-hewed churn of its earnest and energetic performance, one could almost feel the same identity crisis Adams faced in composing such a casual-seeming collision of intellectual rigor and pure sentimentality. Here’s hoping the NSO follows the composer’s lead and more fearlessly plays to its strengths.