All too often those lantern-jawed defenders of the Land of the Free turn out to be little more than devious political opportunists.

Henry Kissinger, Richard Nixon, Oliver North...and now Charlie Wilson.

But - and it's a big but - in Wilson we may have chanced upon someone who was genuinely moved to help a nation's plight merely than deal in fire'n'brimstone anti-Communism.

A heavy-drinker? Yip. A womaniser? Check. An arch political manipulator well-versed in the oily machinations and chicanery of high political office? You got it.

However, Wilson, a Texan democrat, also rubbed against the right-wing grain with his championing of Medicaid, his support of a minimum wage and tax breaks for the elderly.

It was his championing of the Afghan plight during the dark days of the Soviet invasion that made him the toast of America's Kremlin-haters.

Wilson - together with cheesed-off CIA agent Gust Avrakotos (Seymour Hoffman) - clandestinely channelled $500m into a fund for buying sophisticated anti-aircraft gunnery to literally bring down the Soviets.

Director Mike Nichols' likeable biopic takes the form of a lightweight yarn with a satrical script pinpointing the absurdities of the situation as accurately as a Milan surface-to-air missile.

You can't really go wrong with the story especially when you throw in Las Vegas strippers and Julia Roberts as a firebrand Texan socialite and occasional bedpartner of goodtime Charlie.

What makes this really enjoyable, though, is Seymour Hoffman's belligerent turn as Avrakatos, a seasoned operative who's clawed his way up the spook ranks the hard way.

Hanks, on the other hand, is merely adequate as the anti-hero and we could really have done without the scene where a damp-eyed Wilson surveys a teeming refugee camp.

We could have also lost the crass sequence where blazing Soviet helicopter gunships are rendered as nothing more meaningful than the scores in a tacky video arcade shoot 'em up.

What does emerge is a genuine moral crusade albeit one requiring the customary American greasing of palms and granting of favours to get it off the ground.

Slick, sharp and a little sentimental, this is the story of one American hero who may more or less deserve the accolade.

Tim Evans