I would suggest that the image we had when we designed this thing would be something like the American executive branch's selection, not from a given political party, but chosen - probably more affiliated with it than a member - for the capability in that specific function as opposed to other things.
Nous songions à un organisme qui, à la mode américaine, n'appartiendrait pas à un parti politique donné - il serait sans doute davantage affilié -, mais choisi par l'exécutif en raison avant tout de ses compétences dans un domaine précis.