Although Jeb Bush may have been quite conservative by the standards of the 1990s, today he is the voice of the moderate conservative establishment, most comfortable talking about economic growth and opportunity, and about education and immigration as the means to them. And Marco Rubio is running as the future of conservatism—a perfect match of message and messenger.

On the personal front, Mr. Kasich comes across as warm, passionate, almost hectic. Mr. Rubio too is warm—genial, welcoming, a clear and fluent speaker with more self-control than the Ohio governor. Mr. Walker is competent but doesn’t seem as forceful as his record, or quite large enough for the higher office he seeks. Mr. Bush is workmanlike, well-versed in the issues but without the ability to present his positions concisely. Mr. Cruz knows what he wants to say, so much so that he often sounds rehearsed, with an ever-present edge of barely suppressed anger.