For decades, Democratic policies and politicians grew pale and scrawny in the shadow of Franklin Roosevelt. It took Bill Clinton to modernize the Democratic appeal — providing government, at least in theory, with a catalytic, rather than supervisory, role. It is Republicans who now struggle in the shade of presidential greatness, even when they win congressional elections.

Olsen and Wehner point to two serious risks in seeking “a posthumous seal of approval” from Reagan. First, there is the consistent temptation of all idolatry — to craft a figure in our own image. Those who claim Reagan as the first and purest tea party leader find support not in history but in mythology.

The authors make what seems, at first, a fine distinction but turns out to be a decisive one. Reagan’s guiding political principle was not human freedom — the belief of a doctrinaire libertarian — but human dignity. The cause of dignity is served by the ability of individuals to shape their own destiny, something denied in all forms of totalitarianism. But properly limited government can also serve the cause of human dignity. “We accept without reservation,” said Reagan, “our obligation to help the aged, disabled and those unfortunates who, through no fault of their own, must depend on their fellow man.”