In what's meant to be a grown-up Western democracy surely we'd all like to think so. It doesn't pay to be naïve. Politicians, even really honest ones, regularly say things they don't quite believe.
The public knows this. We don't expect our politicians to be angels. But outright lying, in my experience, is relatively rare. It is too easily found out.
Only one senior politician still in the game has ever privately told me something that was utterly, entirely, and completely untrue. It was proved publicly to be a lie a few days later.
It's also rare for opposition parties to accuse a prime minister, on the record, of lying.
Which brings us to Boris Johnson.
The prime minister's relationship with the truth is under intense scrutiny at the moment. He is refusing to give full explanations on some issues. There are questions about how the refurbishment of his Downing Street flat was initially funded, and about incendiary comments he made last autumn as England was about to enter a second lockdown.
Downing Street is repeatedly denying that he has done anything wrong.
It is not the first time in Boris Johnson's long career that he has faced questions about his conduct and character. But the stakes are so much higher now. His unique way of running things - and sometimes chaotic approach to decision-making - has, sources tell me, led exasperated colleagues in No 10 to nickname him "Trolley".