Ronald Reagan: American Idol, BBC Four

Aptly for a programme whose title invokes a show which is all style, no substance, the subject of Ronald Reagan: American Idol is image. What was Reagan really like? How much of his career as a Hollywood star did he carry into office? And why have certain images of Reagan endured? The first question, alas, is the one neither the film nor his biographers nor his family and friends have come close to answering.

The film, directed by Eugene Jarecki and shown to coincide with Reagan's centenary, opens with an ancient clip of Reagan talking about the fictionality of what follows. This tactic – taking a snippet from one of his movies from the late Thirties and Forties – is a cliché of the Reagan biopic genre, and while you can’t take a scriptwriter’s lines as Reagan’s own view, it at least reminds us that he was more skilled an image-maker than most. A man who kept his innermost beliefs even from his wife (Nancy herself has said this), the actor may have taken his craft too much to heart.

The actor’s greatest tool is sincerity, and this Reagan had in abundance. We can believe that his fervent anti-communism, full of fire and fever, developed when he was a spokesman for General Electric touting the benefits of capitalism up and down the country, was genuine, but while he publicly refused to name names to the House of Un-American Activities Committee and its chairman Joseph McCarthy, he was a secret informant of the FBI. He created America's hyper-militarised image to frighten the communists - "Star Wars" and massive weapons programmes were not for use except as symbols of US might.

Again, he pursued Reaganomics, with its over-zealous interpretation of the Laffer Curve and tax cuts for the wealthy and corporations and deregulation of financial markets whose effect we feel today, full tilt, not necessarily because he believed that it would work (it doesn’t) but because he was captured by the sort of corporate interests which helped him in his election to the Californian governorship, the film says.

And he maintained an image of complete silence over Aids, until his son and wife convinced him, in his final presidential year, six years after it had been discovered, to use the word in public.

The film argues, in fact, that there were no theoretical underpinnings or unifying philosophy to his life. So how can you be truly sincere when no one knows what you really think? Reagan’s image since his death in 2004 has suffered the fate of all myths and undergone manipulation for present purposes. It now stands for a set of values which every Republican candidate must say they aspire to – small government, lower taxes, less regulation et al – whether or not Reagan himself believed in or practised them.

Jarecki, who also made Why We Fight, on the excessive role of the military in American life, and The Trials of Henry Kissinger, follows a conventional line through Reagan’s life, relying on over-easy sub-Freudian interpretations – he was a lifeguard when young and thus saw himself as America’s lifeguard, etc – but the truth is that there is no truth, or at least not one he can discern with a cast of journalists as talking heads. Administration officials are few and far between, meaning the sources are at best second-hand. His son, Ron Reagan, further humanises the president, and admits the sort of foibles and failures a conservative talking head could never allow.

Ultimately, the truth is the image. Although he was mocked for starring in B-movies, he had sufficient skill to play the role of a sincere, paternal president. Never mind that Oliver North was funding Nicaraguan terrorists or that Reagan himself was aware that the White House was illegally, impeachably, exchanging arms for hostages with Iran: Reagan knew all the right lines and never missed a cue.

• Watch Ronald Reagan: American Idol on BBC iPlayer
• Find Ronald Reagan's films on Amazon
• Find Eugene Jarecki's films on Amazon