“Well, we’re interrupting this because what the president of the United States is saying, in large part, is absolutely untrue,” said CNBC anchor Shepard Smith as his network pulled away from Donald Trump making baseless post-election claims about illegal voting. As did other networks. Journalism’s belated turn against falsehood should resonate far beyond the US.

Trump’s was the most successful project of political lying in a modern democracy. His 22,000-plus misleading or false claims, as documented by the Washington Post, set a record that may long outlive him. On the upside, he has taught social media and journalism how to deal with future political liars. Facebook and Twitter are finally slapping warnings on his false posts. Now my profession needs to adopt the standards of evidence of the law courts and science.

In Trump’s first five years in politics, journalists fell into the trap of amplifying his falsehoods. When he launched his candidacy in 2015 by claiming that “Mexico” was sending “rapists” north, journalists were caught unawares. They didn’t know how to handle a politician who simply made stuff up. Previous politicians, many of them law graduates, had preferred the lawyer’s trick of using convoluted, weaselly language to muddy the truth. So in 2015, TV channels let Trump keep crying “rapist”. They should have noted that undocumented immigrants appear to have lower crime rates than native-born Americans, then stopped repeating his unfounded claims.