The KISS principle is that people should 'Keep It Simple, Stupid'.
The problem is that politicians think they have to do just that.
The result was Brexit, where it seemed that those campaigning for departure (I stress, those campaigning and not necessarily those who voted) believed that it really was simple.
But it wasn't: far from it. The idea that it was easily possible just was not true, as the evidence has proven: it's fiendishly hard. And getting harder as those who thought it simple have had to be re-educated along the way, to the irritation of the EU, Ireland, business, trade unions and many others.
Whether or not the mess of Brexit will be resolved in the last twenty-four hours before departure remains to be seen. I am now erring towards pessimism. But let's be clear, important as that issue is, it's not the big picture.
The big picture is about the fact that the whole of populism is built on the KISS principle. The idea is that there is a big idea. And it's simple. And that those who don't get it are stupid. And are the be reviled as a result.
That's how politics is developing.
And it is deeply dangerous. The world is much more nuanced than that. And difference requires respect or democracy cannot happen. But we are losing that understanding. Or rather, some are deliberately sweeping it aside. As Fintan O'Toole argues in The Irish Times, what we are now seeing are the trial runs for fascism. The KISS principle summarises exactly what they do.
Unless we're very careful this will end in tears.
Or much worse.