There is a kind of strange fascination in watching the GOP nominate a candidate for the office of President of the United States. Some might call it a nightmare. It would have been impossible to predict 12 months ago that the cartoonish Donald J Trump would be the clear front-runner and that the gargoyle-like Ted Cruz would be the only person with a chance of catching him. Both being so different - Trump the narcissistic deal-maker, Cruz the doctrinaire conservative - they form a kind of analysis-defeating top two from the pages of a racy political thriller, the one you know could never, ever happen in the real world. But there you go, as Reagan might have said, for this is how the world is turning.

Having watched the GOP debates and segments of Trump rallies, it is clear that this man should not be taken lightly and that it is entirely possible that he will win in November. This is not because he is coherent, has policies beyond the slogans, shows Presidential metal or gravitas, or is able to command the facts. He is the opposite of all these things. But he has an energy, showmanship and an ability to change defense into attack, that should be regarded by Democrats as potentially lethal to any Clinton contest for the top job.

Don't say I didn't warn you.