Nicolas Roeg's projects are variable to say the least, but are never less than interesting. "Insignificance" is obviously, first and foremost, an adapted stageplay: it's wordy and pretty-much 'room-bound'. BUT, it pays to view this film more than once: the underlying themes are not overtly presented and, what's more, it takes a while to adjust to the juxtaposition and role-reversals of the four protagonists: Einstein, McCarthy, Munroe, and DiMaggio.
Einstein is wracked by guilt over Hiroshima yet fancies the simplicity of a sexual liaison with Munro; Munro is sick of being seen as a bimbo and craves intellectual credence; Senator McCarthy is at the height of his witch-hunting powers but is an impotent sleazebag; DiMaggio is insecure about his celebrity, self-obsessed, and prone to violence. Each of them contains the seeds of their own destruction. Each character has a troubled, abused/abusive past and a questionable future. Gradually, we see that obsession itself is the central theme. America's obsession with its postwar cultural icons and mores; the obsessions of the protagonists for something none can have: peace-of-mind and/or happiness.
Compared with the theory of relativity, a proposed unified-field theory and, indeed, the cosmos itself, all the aspirations and interactions of Roeg's protagonists seem insignificant. Yet these aspects of the physical universe (it's all quantum, trust me!) affect us when they are applied to the development of the means to destroy us. Monroe's mention of the principle behind the neutron-bomb (without naming it as such) is not an anachronism per se, but can only be understood by a contemporary audience. Indeed, ALL the references within the script are only accessible to a knowledgeable viewer: one au fait with '50s occurrences/personality cults and how they affect us in the 21st century.
This film and its screenplay are either very, very clever, or extremely opaque and pretentious. Ultimately, however, probably insignificant.
live long and prosper :)

This film had no huge stars in it, but did have a very good cast filled with excellent supporting actors AND Gene Tierney before she became a big star. With George Sanders, Reginald Gardner, Harry Carey, Bruce Cabot, Jospeh Calleia and Cederic Hardwicke, you'd expect more from the film than it actually delivered. Most of this, I suspect, is because of a second-rate script, as director Henry Hathaway was a competent and well-established man at the helm.
The film is set in East Africa during WWII--just before the Americans entered the war. The Brits are trying to control their African colonies while subversive Nazi elements are trying to stir up trouble among the locals. One of the white men in the film is a double-dealer--working for the destruction of the British Empire! But, lovely Tierney, playing a sultan's daughter(!), is out to help save the day for good ol' Britain.
American film makers have long sided with the Empire and the 1930s and 40s saw a plethora of pro-empire films. Nowadays, with changed sensibilities, the notion of seeing the happy black natives dying for Queen and country seems ridiculous--and it would be hard to root for either side! Still, in its day, this propaganda piece was effective in drumming up support for the British--though when seen today, the film suffers from a long-winded script and silly casting. The one bright moment in the film is the final showdown between George Sanders and the enemy agent. Too bad after such a potent scene the film just seemed to talk and talk--losing some of its punch.