Hugely charming when he wants to be, but with a changeability that can turn on a dime to appalling evil, Whitaker's Amin is a man with an iron whim who engages a Scottish doctor as his personal physician after being impressed with his handling of a roadside emergency. This is a fictionalized version of the dictator's rise, wallow in excess and lurch toward the abyss as seen by the brash young medic, based on the acclaimed 1998 novel by Giles Foden.

One improvement screenwriters Peter Morgan ("The Queen") and Jeremy Brock ("Mrs. Brown") make at the outset is turning the relatively bland do-gooder Scotsman of the book into a brash, cocky young adventurer who's ready for anything. Upgrade results in a Nicholas Garrigan, agreeably if not always sympathetically played by James McAvoy, who's not only more entertaining than his counterpart on the printed page, but more plausible as a devil-may-care guy who boldly speaks his mind to Amin while others cower in fright.

Picking Uganda virtually at random as a place where his new medical degree could be put to good use, Nicholas is first stationed at a remote village where he instantly puts the moves on older woman Sarah Merrit (Gillian Anderson), the attractive wife of the area's hard-working British physician (Adam Kotz). It's 1971, and together Nicholas and Sarah attend a rousing back-country rally where Amin, having just ousted the country's corrupt, communist-leaning leader, Milton Obote, dazzles the locals as well as the naive newcomer, to Sarah's consternation.

After the president's injured hand is neatly bandaged by Nicholas and he realizes the heritage of his chance benefactor, Amin, who long served in the King's African Rifles, sings the praises of the Scottish, deeming them among the bravest fighters on Earth. Director Macdonald, a Scotsman himself, stages a hilarious scene in which Amin appears at a public ceremony wearing a kilt surrounded by Africans performing a Scottish song.

Any misgivings erased by Amin's evident affinity for him, not to mention the leader's genuinely ingratiating persuasiveness, Nicholas accepts his new job and immediately reaps the rewards: a nice apartment within the immaculate presidential compound, a Mercedes convertible, women personally selected by Amin and, above all, unrestricted access to the big boss himself, who deliberately denigrates other members of his inner circle by calling Nicholas his closest adviser.

An alarming episode that only serves to strengthen the bond between the two men has Amin impulsively asking Nicholas to drive him to the airport in the convertible. En route, Amin's limousine, traveling ahead, is ambushed by gunmen. The aftermath, when the would-be assassins are dealt with, reveals to Nicholas the extent of Amin's fury for the first time.

This entire first section is quite engaging for several reasons: the fluky circumstances creating the main characters' bond (Amin's actual physician was Scottish, although much older), Whitaker's utterly convincing portrayal of Amin's larger-than-life appeal and moodiness, and the view the film provides of a rarely seen location, the attractively modern capital Kampala. This is reportedly the first Western production to shoot in Uganda since the second unit of "The African Queen" 56 years ago, and certainly the first time its main city has been shown. To have the action play out in its proper setting adds immensely to pic's interest.

Before long, however, intimations of Amin's misdeeds begin accumulating; judges, rival politicians and others go "missing," and Nicholas gets in hot water when he treats one of his boss's many children, an epileptic boy, and becomes ill-advisedly involved with the mother, Kay (Kerry Washington), an out-of-favor wife of the president.

No matter how impudent Nicholas is capable of being, and no matter how drunk at the time, his rash decision to get it on with a Mrs. Amin is ludicrous; it's a ruinous narrative ploy that signals the undue melodrama that overtakes the picture from this point on. Nicholas' fate and efforts to escape Uganda are linked to the pro-Palestinian hijacking of an Air France and the subsequent Israeli raid on Entebbe Airport, during which he suffers cruel and unusual punishment of the same nature as that endured by Richard Harris in "A Man Called Horse."

In the end, "The Last King of Scotland" is much better when it plays it cool and amusing than when it tries to ramp up outrage and indignation. Among its grace notes is the equivocal portrayal of British interests in the former colony, most prominently repped by an oily, persistent Foreign Service officer (an effective Simon McBurney) who's not as clueless as he seems. The debauchery of Amin's private life is glancingly conveyed by raucous party scenes; at one of them, Amin watches "Deep Throat" and seeks Nicholas' expert advice on the physiological possibility of Linda Lovelace's purported clitoral condition.

Drama moves along speedily, although there's a hasty, unartful look to the picture in general that lacks distinction.
 
Camera (Deluxe color, Panavision widescreen), Anthony Dod Mantle; editor, Justine Wright; music, Alex Heffes; production designer, Michael Carlin; supervising art director, Lynne Huitson; art director, Joannah Stutchbury; set decorator, Tina Jones; sound (Dolby Digital), Michael Wollmann; re-recording mixer, Martin Steyer; line producer, Andrew Wood; assistant director, George Every; second unit director, Jonathan Bloom. Reviewed at Telluride Film Festival, Sept. 2, 2006. (Also in Toronto Film Festival.) MPAA Rating: R. Running time: 121 MIN.