An intriguing historical episode is treated tepidly in Peter Webber’s misshapen docu-drama about the American decision about how to deal with Emperor Hirohito in the aftermath of Japan’s surrender in 1945. The question was whether Hirohito, who in the minds of many Americans was seen as no better than Hitler, should be dealt with as a war criminal, stripped of his power and put on trial along with the members of his government. And the answer was to be determined—quickly—by General Douglas MacArthur, who had been appointed to oversee Japan’s postwar reconstruction armed with virtually dictatorial powers. He appointed Brigadier General Bonner Fellers, who had some acquaintance with the country, to investigate whether the Emperor had played an active role in the war effort or simply acquiesced in it more as a passive observer.

So long as “Emperor” sticks to the diplomacy at work in this business—made difficult because the Emperor was traditionally thought to possess divine status, and any effort to depose him could set off a popular uprising—it’s a solid if rather stolid piece of work, necessarily embellished for dramatic effect. It’s helped immeasurably by Tommy Lee Jones’s colorful turn as MacArthur. He brings the same tone of gruff cantankerousness to the General that he did to Thaddeus Stevens in “Lincoln,” as well as a similar measure of self-serving manipulation and charm, and he’s great fun to watch, particularly in the final sequence when the General meets Hirohito (Takataro Kataoka) and blatantly violates all the expected diplomatic niceties, but to good effect.

But MacArthur is really a supporting character here. The bulk of screen time goes to Matthew Fox as Fellers, and to his backstory romance with Aya (Eriko Halsune), a Japanese girl he met in college and followed to Japan when she returned there. There are tons of flashbacks to their doomed relationship, and they’re played like mawkish melodrama. It’s doesn’t help that he’s compelled to play much younger than his real age in the college scenes—unconvincingly (this is an instance when another actor should have been substituted)—but throughout he’s little more than a bland lovesick swain, totally outclassed by Jones in their scenes together, and by the fine Japanese performers he appears with elsewhere. (like Masayoshi Haneda as his driver Takahashi, who creates a sympathetic figure even though the script employs him merely as someone who can teach Fellers a lesson about how much more the Japanese have lost than he has.

It’s too bad that “Emperor” devotes so much time to Fellers, because the episode it focuses on not only possess inherent interest, but can serve as a reminder of the benefit that can come from treating a defeated enemy with respect rather than contempt and taking risks for future gain. And though much of the picture is shot in relatively drab offices and only slightly more opulent living accommodations for the Army brass, it does boast some impressive visuals—the opening images of the country ravaged by Allied bombing and a few exteriors of the Imperial Palace stand out in Stuart Dryburgh’s excellent widescreen cinematography. The other technical aspects of the production are adequate but hardly sufficient to endow it with real epic sweep.

“Emperor” winds up as a decent history lesson—even if one told with a major dose of dramatic license—that’s dragged down by a sappy, clumsily played romantic subplot. Still, Jones is on hand often enough to make it palatable, though not much more than that.