Conor McGregor's a living legend to his Irish fans ... but Ireland's 2nd biggest UFC star says he is NOT cut out for a political career back home.
We asked "Irish" Joe Duffy about McGregor pulling a Trump when his fighting days are done -- something Conor teased when we got him out in NYC last month.
Joe -- who fought and beat Conor back in the day -- was super complimentary of McGregor as a fighter, but told us why a run for office wouldn't end well for him.