We are now seeing the collapse of truth in politics.

The system is being ripped apart by the outrageous lies of Brexit on one side of the Atlantic and the rise of Donald Trump on the other.

As Jonathan Freedland writes in The Guardian, we are now in the era of post-truth politics where an unhesitating liar can be king.

“Donald Trump enjoys a relationship to the truth that is chilly, occasional and distant,’’ Freedland writes. “The Washington Post’s fact-checker blog has awarded its maximum dishonesty rating – four Pinocchios – to nearly 70% of the Trump statements it has vetted. And it’s vetted a lot. That doesn’t mean the other 30% turned out to be true. They just earned three Pinocchios rather than the full four, which means the Post found a shrivelled kernel of veracity wrapped inside the thick layers of fraud, distortion and deception.”

The same, he said, was happening on the other side of the Atlantic when the Brexit campaign was cranking up.

And that has massive consequences for society. As Katherine Vinerpoints out, the era of Facebook and social networks has caught us in a series of confusing battles between opposing forces: between truth and falsehood, fact and rumour, kindness and cruelty; between the few and the many, the connected and the alienated.

“In the digital age, it is easier than ever to publish false information, which is quickly shared and taken to be true – as we often see in emergency situations, when news is breaking in real time,’’ Viner writes. “To pick one example among many, during the November 2015 Paris terror attacks, rumours quickly spread on social media that the Louvre and Pompidou Centre had been hit, and that François Hollande had suffered a stroke. Trusted news organisations are needed to debunk such tall tales.

“Sometimes rumours like these spread out of panic, sometimes out of malice, and sometimes deliberate manipulation, in which a corporation or regime pays people to convey their message.”

The Economist says post-truth politics is different from political lying.

“Once, the purpose of political lying was to create a false view of the world. The lies of men like Mr Trump do not work like that. They are not intended to convince the elites, whom their target voters neither trust nor like, but to reinforce prejudices.

“Feelings, not facts, are what matter in this sort of campaigning. Their opponents’ disbelief validates the us-versus-them mindset that outsider candidates thrive on. And if your opponents focus on trying to show your facts are wrong, they have to fight on the ground you have chosen.”

Post truth politics has two parents.

One is anger. Many voters feel let down and left behind, while the elites who are in charge have thrived. They are scornful of the self-serving technocrats who said that the euro would improve their lives and that Saddam Hussein had weapons of mass destruction. Popular trust in expert opinion and established institutions has tumbled across Western democracies.

Post-truth has also been abetted by the fragmentation of the media, creating an atomised world in which lies, rumour and gossip spread with alarming speed.

Even if Trump loses the election, post truth politics is not going to disappear. It’s been too successful for it to disappear.