From Plato's Noble Lie to Machiavelli's cynicism to modern day populism, lying in politics has been seen as a threat to social life. Opinions obviously vary from Augustin's view that all forms of mendacity are evil to Kant's universal principles. However, Hannah Arendt argued that telling the truth in politics has never been seen as a political virtue. From a sociological perspective, it could be argued that lying is always corrosive of trust and a threat to 'social capital'. There is some general agreement though that lying (the 'white lie' for example) is acceptable if it has beneficial outcomes. This position is known in philosophy as 'consequentialism'.
As a result, truth testing becomes the basic practical problem. This study of lying and truth testing starts with a consideration of the role of the oath and the confession in legal proceedings. The oath, especially sworn over a bible, was a traditional instrument of truth telling. Many legal experts, such as Jeremy Bentham, dismissed the oath as unreliable. With the secularization of society, the traditional oath has all but disappeared. The confession, if given with copious signs of remorse, was welcomed by judges as a sign of a reliable witness. Lie detectors have been introduced to test confessional claims to truth, but these are also unreliable. AI may be the next stage.
Despite Arendt's depressing observation about politics and lies, lying is now seen to be a major problem in modern political life. There has been growing public concern about political issues that are closely associated with populism and the Presidency of Donald Trump. Similar problems had attended the Presidencies of both Richard Nixon and Bill Clinton. Faced with the challenge of public lies and fake news, many observers have concluded we are in the age of Post-Truth.