Whether Donald Trump emerges from the Republican convention as the GOP presidential nominee is an open question at the moment. I happen to believe that he will; but it is theoretically possible that he will not—and we might well see a brokered convention, or a fractured convention, in Cleveland next week.

The possibility of a contested convention was first raised when Trump appeared to be winning the primary season, and especially among Trump supporters, the mere mention of it was greeted with incredulity and horror. But the fact is that, until comparatively recently, brokered conventions were the rule, not the exception, in American politics. And you could argue, as I have elsewhere, that both parties have benefited historically from brokered conventions.