Matteo Sciabordi, left, and Laz Alonso star in Spike Lee's Miracle

Poor Spike Lee. You just knew, the moment he lashed out at Clint Eastwood for leaving black soldiers out of his two-part Iwo Jima epic, that he had really put his foot in it.

And now here’s proof. “Miracle at St. Anna” is Lee’s sloppy, absurdly long mashup of combat film cliches. While Lee aimed to make this adaptation of James McBride’s novel an epic of the African-American experience in the war, the flimsy material, hammy performances, wasted characters and wasted time betray one inescapable fact: What Spike doesn’t know about World War II, or even good World War II movies, would fill a book.

The story spins off a real incident, an SS massacre of Italian civilians in the latter stages of the Italian campaign. Miracle at St. Anna ties that incident to a fictional one involving the real-life 92nd Infantry Division, the only African-American unit (led by white officers) to see combat in Italy.

The story is framed in a flashback. In 1983, an aged New York postal clerk shoots a customer he seems to recognize from long ago. A jaded cop (John Turturro, overstocked with cop banter) and a cub reporter (Joseph Gordon-Levitt) try to figure out why. They don’t, but a flashback lets us in on the secret.

In 1944, four “Buffalo Soldiers” from the 92nd found themselves behind German lines in the mountains of Tuscany. They befriend locals, including a mystical, shell-shocked child who sees his savior, the hulking, simple and superstitious Train (Omar Benson Miller), as a “Chocolate Giant.” Train totes around this Italian bust, which he rubs for luck. The fetching Renata (Valentina Cervi) comes between two sergeants, the straight-arrow Stamps (Derek Luke) and the swaggering Bishop (Michael Ealy). The Puerto Rican Hector (Laz Alonso) operates the radio and translates.

The colorful townspeople, the heroic partisan resistance fighters, urbane Nazis who read and quote poetry, incompetent and racist American officers – Lee and McBride have conjured up a rich tapestry of recycled war-movie tropes. Characters pause to have sex, remember racist incidents back home, rail about “the white man’s war” and ponder the racial “progress” they represent. Lee intercuts between the common prayers of Italians, African-Americans and Germans as combat looms.

A scene set in 1983 mocks the John Wayne hokum of “The Longest Day,” which the postal clerk vet watches on TV. Lee falls into many of that movie’s excesses. With the exception of Luke, his actors don’t carry themselves as soldiers, even bad ones. The tough G.I. slang sounds anachronistic, and the cliches seem borrowed without understanding them. A soldier trapped in the middle of an open field during a firefight yells “Cover me!” as though it’s something he (or Lee) heard in a movie.

Filler scenes and pointless characters – John Leguizamo is in Italy in 1983; why? – stretch what could have been a lively minor adventure mystery into an ordeal that panders when it doesn’t ponder.

It’s not Lee’s worst film. But its tone deafness connects it with an infamous list that includes “She Hate Me,” “Girl 6” and “Bamboozled.” He wanted to make his war movie, and I love a good war film. Perhaps Lee should have watched a few good ones before tackling this. I hear Clint Eastwood has made a couple.