While I was living in Madrid, the Filmoteca showed both the American version and the little-seen European version of this. My memory is a little hazy, but the European version was by far the more interesting of the two: firstly Hammond is seen to go just that much further into fascism; and secondly, rather than have him nobly struck down at the end, Pendie actually chooses NOT to save him, because she sees what he has become. I've yet to find anything written about this other version though. I think we should be told...
Review of Gabriel Over the White House
