All the King’s Men should be one meaty movie — a platter of political pawn movement with a side of sultry Southern secrets, all chased with a throat-stinging shot of whiskey.

What is served is more fatty and gristly dialogue than high-talent actors like Sean Penn, James Gandolfini, Kate Winslet and Anthony Hopkins can cut through and a miserably watered-down performance by an out-of-his-element Jude Law.

Not surprisingly, writer-director Steven Zaillian’s adaptation of novelist Robert Penn Warren’s juicy tale of machination and manipulation is like most novels crammed into two hours — it gets the job done quickly and efficiently in the same way as a visit to the drive-thru.

The third act undeniably captivates with its shadowy pulled strings. But seductive, corrosive effects of power and corruption often take a backseat to who married whom in what financial state.

James Horner’s overbearing score of crescendoing bells and percussion, combined with dialogue either frustratingly folksy or a bunch of philosophically empty babble, are self-important trickery. Zaillian’s take on the book is a greased-palm mystery with a cast that’s half perfect, half awful.

Penn at least tries making the movie gigantic before it makes him small. With wildly windblown hair and a bulky midsection, his Willie Stark is a good ole’ boy county treasurer in 1950s Louisiana ready to quit politics after cries of construction graft on a schoolhouse go unheard.

The schoolhouse’s collapse — which kills three — rings up the political ladder to party boss Tiny Duffy (Gandolfini, sounding like Tony Soprano eating jambalaya in Jersey.) Willie accepts Tiny’s backing of a gubernatorial run, only to learn he’s been set up as a third-candidate vote splitter.

Once Willie goes off book from Tiny’s speeches at a rural carnival, every single man, woman and child in attendance is galvanized by Willie’s pledge to “nail up” corrupt politicos. As an overwrought exclamation point, Tiny tumbles into a pile of pig poop at the moment his scam is called out. Repeating Willie’s speech / rants throughout is just sound and fury, signifying nothing.

Covering the race is reporter Jack Burden (Law), raised in old money by his godfather, Judge Irwin (Hopkins, both gentle and genteel in the movie’s best performance). Disillusioned by his challenged endorsements of Willie, Jack quits the paper and becomes Willie’s right-hand man.

Running the state, but facing possibly trumped-up impeachment charges, Willie asks Jack to dig dirt on Irwin, who has publicly backed the proceedings. Jack’s childhood friends Adam (Mark Ruffalo) and Anne (Winslet) also are sucked into Willie’s sphere, which isn’t so well-rounded.

The whole movie is told in high-point shorthand, as there’s no slow fall into corruption for Willie. All of a sudden, he’s hiring tough guys with guns, cheating on his wife (and mistress, well played by Patricia Clarkson) and authorizing underhanded tactics. For the attention paid it, Willie’s changed mind might as well be from a switch to two fingers of booze from orange pop with two straws.

In one moment of precious narration, Jack likens peripheral noise to “something you hear, but not clear enough to catch the meaning of.” The same goes for a fatal amount of cornpone dialogue like “Sometime ain’t never now” and “It was long buried in the past like a dead cat in the backyard.”

Zaillian needs something to make up for Law’s worst-ever performance — flippant, vacant and incapable of showing how hatchet-man work is crushing Jack’s long-held ideals. Like the wasted Winslet and Ruffalo, Law’s also too old — all three are laughably made to look like teens in Great Gatsby-style flashbacks in roles that require a youthful intensity and zeal to be snuffed out.

A heated exchange between Law and Ruffalo descends into “I think”-“You think” nonsense. These actors aren’t sparring with each other, they’re feinting and jabbing into stifling, stale air. All the King’s Men is dead and encased like an amber fossil, and offers little of what such an artifact might tell us of our past, present or future.