The amusing comic above pinpoints a serendipitous linguistic truth with regards to the expression 'con man'. A con man is nothing more than a confidence trickster and to con someone entails gaining their confidence through deceit and cunning.
It could be argued, moreover, that it helps to be con-fident (from the Latin con, with and fidere, to place trust in), or at least project an outgoing image of confidence, as did the iconic creator/business man Walter Disney - who privately was an insecure and shy man (at least according to his Wikipedia entry) - in order precisely to inspire confidence in others so that, if such is the intended purpose, they may be conned, i.e. misplace their faith.
Successful politicians, such as US presidents, are masters at inspiring confidence in their populations giving a firm, sometimes friendly, face to a heinous imperial power and agenda.
As the movie Back to the Future observes, Reagan's acting career would no doubt have helped him give off an effective, TV-friendly appearance as President in order precisely to inspire confidence and therefore con the American public which, let's face it, is the prime skill required of any presidential figurehead owned by bankers and other established spheres of interested influence.
Barack Obama went back during his presidential tenure on practically the entirety of his campaign promises (see this video by James Corbett https://www.youtube.com/watch?v=oeDZIyGkGNM) and yet, despite the continuous lying, enjoys a vast approval rating now that he has finished his two-term presidency because he and his team have managed to engineer an image of affable, competent, man-of-the-people, straight-talking, unphased and cool respectability.
To take these points further, one could say that psychopathic individuals - of which the political realm has no shortage - are the masters of confidence trickery as they are well known to give out surface, seductive charm in plenty and as being able to mimic relatable human emotions. This is on top of the natural predisposition and expertise they possess at manipulating others, e.g. by gas lighting them and subversively and covertly managing their perception, e.g. through transference of blame.