Writer-director Lucy Walker’s Countdown to Zero follows in a line back to 1945 of fact and fictionalized fact about post-Manhattan Project Armageddon. Warnings come on the printed page, on the small and the silver screen, in song: Hersey, Shute, Duras and Vonnegut; Wise, Resnais, Lumet, Meyer, Werner, Spottiswoode; Barry McGuire, Bobs Dylan and Marley.

Rogue and unstable states and non-state terrorists have displaced Cold and Star Wars bogeymen, but the sword of nuclear annihilation still hangs by a thread even when shoved momentarily to back burners by climate change, oil spills, endangered species, water and financial crises.

In view of North Korea, Iran, Bin Laden, among many, only an ostrich would shrug or argue with the ninety-minute thesis in this Sundance and Cannes selection developed through socially concerned partners and backing. Unlike that of An Inconvenient Truth, this defining idea is not open to discussion: dwarfing Big Boy and Fat Boy, nuclear technology and capability menace the Earth, for, once upon a time confined to safe hands, i.e., ours, they are today possessed by others and soon to be by still more, friends, foes, the sane and the insane. The conclusion, the plea pitched, is for a nuclear weapons-free world, no stockpiles, no silos, no warheads, no nothing. Ironically, one of the semi-good guys is Ronald Reagan, even if he and Gorbachev did not quite make it in 1986 Reykjavik.

In non-fictions with “experts” one should weigh the value of such expertise and bear in mind that speakers are edited in or out according to stance and charisma. While printed affiliations guarantee nothing, heads here do present frightening assessments, mixed with archival footage -- Robert Oppenheimer -- and an excess of multi-language guesstimates from the confused man and woman in the street.

In whatever medium, advocacy journalism is unlikely to change people’s minds, since it will be seen, heard or read precisely by those already members of its choir. Though without converting, preachment may reach a wider audience as a result of calculated presentation as much as of content, such as through the winning persona of Al Gore in his particular filmed lecture.

In Walker’s, on the other hand, while some talk more often or longer, there is no narrational voice as such. Interspersed with satellite and ground-level images of metropolises -- underground, too, for New York’s vulnerable subway appears often (and the end is an overlong Times Square New Year’s Eve countdown celebration) -- basics are spelled out (written down, in fact), expounded upon, exemplified in outside footage, and reiterated.

The technology to make and deliver a nuclear WMD is today less rocket science than slightly costly child’s play. The problem lies, rather, in obtaining HEU, Highly Enriched Uraniam, or plutonium, for which materials a black market has developed, from the former Soviet Union, through Georgia, and on to who knows where. The nine-nation Nuclear Club has three to four dozen aspirants kicking on the door, more than a couple of them saber rattling or deranged.

Mostly in short news footage, the callous mercenary smugglers are shown, and their clients among fanatics, maniacs seeking recognition, revenge or rule. Equal time is devoted to dangers from the good side, again i.e. ours, from the meshuggah General Jack D. Rippers to the mistakes, misunderstandings and misapprehensions that override fail-safe systems. A few of the near-catastrophic miscues considered are common knowledge; many more are not. Some decisions in high places are also familiar, like those of Cuban Missile Crisis brinksmanship; the numbers and nature of others are not.

With appeal to President Obama, a list of statistics and another of steps to be taken ASAP, Countdown to Zero is a sincere editorial with images. That, however, does not make cinema. 

(Released by Magnolia Pictures; not rated "PG" for thematic material, images of destruction and incidental smoking.)