After his blustery, action-man work on The Kingdom, which turned the Middle Eastern quagmire into an explosives-packed demonstration of American heroism in action, screenwriter Matthew Michael Carnahan attempts to deliver its talky, thought-provoking antidote with his Lions for Lambs. It's a big mystery, though, why he chose essentially to write a stage play — and a preachy, immobile one at that. Carnahan's three-pronged assault on national security and the war on terror adheres, in two of those prongs, to the ebb and flow of conversations, with a notional attempt to escape the deadening inertia of enclosed spaces with a third strand about an American military assault on an Afghan mountaintop.

With a canvas this limited and static, and a director as notoriously unadventurous as Robert Redford at the helm, the discourse had better sizzle with intelligence and compulsion. But while Lambs' verbal blitzkrieg does deliver some incisive blows, too much of it rolls off the actors' tongues as proselytizing — and startlingly basic for anyone who doesn't get their news from USA Today. The film's big guns — Tom Cruise as a hawkish Republican senator flogging his latest "roadmap to victory" in Afghanistan, and Meryl Streep as the dismayed political journalist invited to break the story — are confined to the senator's oak-panelled chambers for a verbal sparring session that sounds like newspaper headlines being read out by A-list stars. The other, arguably more pertinent conversation occurs between Redford's political science professor attempting to stir his star student (Garfield) out of apathetic cynicism and into political engagement. In the combat storyline, Special Forces duo Pena and Luke end up stranded behind Taliban lines after their unit's botched helicopter assault, while flashbacks dovetail them back to Redford's class.

What electric charge there is to be had comes from the performances, with the Redford-Garfield and Cruise-Streep tête-à-têtes occasionally making hairs stand to attention. Redford always comes armed with charisma and nobility, and Brit actor Garfield holds his own in their frank, confrontational exchanges. Cruise also nails his role as the youthful neo-con with presidential ambitions, but Streep is too often left stranded, confined largely to arching her eyebrows sadly and skeptically at the spiel her character's fed, and having an unpersuasive meltdown back at her office about the media's complicity in the war.

Redford and Carnahan also strive for balance — allowing space for both sides of the argument and not slamming Cruise's self-regarding senator against the wall with too much force — but there's never an iota of doubt where Lambs' true sensibilities lie, so its efforts in this respect come off as a token gestures. The grand message here is not that war kills, but apathy does. Packaged in a declamatory theater piece, it doesn't get through as resoundingly as it needed to, but the biggest blemish of all is simply that Lambs feels five years too late.