Free jazz! Free Mandela! Chicago Jazz Philharmonic at Millennium Park

"Is it an orchestra?" Orbert Davis asked from the bandstand. "Or is it jazz?"

The leader of the Chicago Jazz Philharmonic posed the question tonight at a Millennium Park concert dedicated to Nelson Mandela. The unasked question: How does mixing European symphony and American swing produce a tribute to South Africa?

With a gospel choir, it turns out. With orations that recall Copland's "Lincoln Portrait, performed with fervor by actress T'Keyah Crystal Keymah. (An windbag introduction by cable documentarian Bill Kurtis underscored what fortunate casting that was.) And in a nod to a Grant Park perennial, Tchaikovsky's "1812 Overture," with extended quotes from a national anthem that brought the pavilion audience to its feet, some listeners with fist raised.

That and an African National Congress marching anthem, performers stomping in time, were the few obvious African references in the premiere of Davis' score, "Hope in Action," performed as a 90th-birthday salute to Mandela. Speaking from the conducting platform, Davis said he was inspired by Mandela's autobiography and from the PBS travelogue "Grannies on Safari." That alone should have told listeners they would not mistake the proceedings for a Mahotella Queens concert.

Davis' program notes suggests his inspiration was not literal. He offered the ensemble as a metaphor for the fight against apartheid: "When musicians are willing to create outside their personal and musical boundaries, they in essence produce a new genre and creative aesthetic."

Political themes in summer concerts tend to be flag-wavers, and the music that accompanied Mandela's quotations was, well, quotidian. But the rhythm section of Ryan Cohan on piano, Stewart Miller on bass and Ernie Adams on drums seemed particularly sharp in supporting the modal flights of Zim Ngqawana on alto and soprano sax and Ari Brown on tenor. They bespoke freedom in a way the recitations could not match.

The rest of the program struggled for its footing in this tug of war between classical and jazz idioms. But jazz arrangements with strings are so rare that it's always a pleasure to hear the Chicago Jazz Ensemble take them on. Dee Alexander reached for common ground in folk with two Miriam Makeba tunes, and got just comfortable enough with her lead sheets for a Dinah Washington flirtation in the Sid Wayne-Quincy Jones confection "Relax Max."

Davis' remaining charts were part Stravinsky, part Gil Evans. They included "100 Questions, One Answer," in which Brown and Ngqawana took freestyle solo turns with Nicole Mitchell on piccolo and Davis on a Leroy Anderson-style trumpet that reminded me of when I played "The Toy Trumpet" behind Clark Terry in a high-school clinic, and ended with a too-short quartet that held the potential for operatic drama.

Personal note: My time as a backup music critic in the provinces is long gone. Back then I enjoyed the luxury of writing the next day and did not have to sprint for the exit with the final note. Arriving just in time at the Pritzker Pavilion, I found a good seat next to Chicago Tribune colleague Howard Reich, with whom I have had occasional newsroom and lunchroom chats. We couldn't talk this time because he had to make himself scarce to write his review. I've never told him how highly I regard such deadline improvisation. It's a salute to his subjects, and this review is a salute to him.