The limits of engineering
Of course, raw IQ is in and of itself largely meaningless in terms of assessing the ability of any given person to lead and manage a complex organisation or system.
The records of various past Presidents show clearly the truth behind that statement. Very few people, if any, would seriously argue that Jimmy Carter did not have greater raw intelligence than Ronald Reagan - yet President Carter proved to be hopelessly inept and was for a while a real contender for the title of "Worst President of the 20th Century". (Given Franklin Delano Roosevelt's actual record during the Great Depression, that takes some serious ineptitude.)
Meanwhile, President Reagan is regarded - rightly - as the man who brought America back to greatness, who won the Cold War, who ushered in a new era of American hyperpower dominance, and whose Administration created over 17 million jobs in its eight years in office.
Intelligence alone is a poor metric for understanding leadership capability, especially in political office, because it gives no insight whatsoever into the ideological vision or blueprint that a given leader might follow.
Prof. Thomas Sowell addressed this question in his classic book, A Conflict of Visions, in which he argued that the traditional Left-Right spectrum of political debate is misleading, and that the real argument is in fact between the Utopians and the Realists. (Note - those are my terms, not Prof. Sowell's.)
The Utopians look at Man as a perfectible creature who, in his natural state, is noble, decent, and honourable, and simply requires firm guidance and stewardship by an enlightened caste of rulers to bring him back to that state. They believe that Man will always opt to do good things, provided that he is returned to his most "natural" state of being - whatever that means in practice - by those who rule over him.
Therefore, to the Utopians, all that must be done is to engineer one's way around the problems of human misery: greed, inequality, poverty, hunger, disease, and so on.
The Realists look at Man as he is - flawed, Fallen, irretrievably broken. In stark contrast to their Utopian counterparts, they see that Man is capable of both great good and terrible evil when unchecked by morality or law. As such, the Realists seek to maximise incentives for Man to do good, and constrain his capacity for evil through laws that stop him from harming his fellows.
It is not difficult to figure out which group tends to be right more often about human nature.
One of the most egregiously terrible examples of the "engineering" mentality in recorded US history comes from a source that some might find surprising: the Administration of President Herbert Hoover.
President Hoover is remembered - incorrectly - as the man who basically stood by and let the Great Depression happen. Up until about twenty years ago, the consensus among academics and scholars was that President Hoover's inaction and laissez-faire economic policies led to a multi-year depression, and that it was his successor, the "legendary" President Franklin D. Roosevelt, who brought America out of its worst-ever economic contraction.
That history is completely wrong.
The reality was radically different. The root cause of the Great Depression has been well explained many times by the Austrian School of economics; it was, in essence, caused by the collapse of a massive credit bubble that grew during the 1920s due to very loose Federal Reserve monetary policy, which then tightened rapidly in 1928 and 1929.
The results of that contraction in money are well known. Unemployment skyrocketed from 2% or so in 1925, to nearly 12% in 1930. Economic activity plunged, thousands of firms went out of business overnight, and the United States of America experienced an extremely sharp and painful recession.
What most people do not know - and what is still not taught in most American schools and universities - is the fact that, by mid-1930, the economy had actually begun a very clear recovery. Unemployment had dropped to roughly 6% by that time - still very high by recent historical standards, but nowhere near as bad as the brutal double-digit rates from January 1930.
The fact that the old lies about Hoover's "inaction" dooming the economy, and Roosevelt's "bold progressive steps" to save it, are still taught as Gospel in American schools (and around the world, too) should tell you everything you need to know about the quality, or lack thereof, of American public education, really.
President Hoover's reactions were the classic response of a very gifted and talented engineer to a distinctly non-mathematical problem. No one argues or doubts that President Hoover was a very brilliant man - in fact, he was too clever by half for his own good, which is why his old boss, Calvin Coolidge, used to call him "Wonder Boy". It was not a term of endearment.
In fact, it is President Coolidge who presents the greatest contrast in style, temperament, and intelligence to President Hoover.
President Coolidge has not been treated too kindly by most historians, who dismiss him as something of an intellectual lightweight and a "do-nothing" sort of President. But this is simply not true. President Coolidge was not prone to wordiness or speeches, but he was extraordinarily smart - and he had no problem sticking up for things that he believed to be right:
More than anything else, though, President Coolidge was a Realist, whereas President Hoover was a Utopian. As such, when presented with a similar economic catastrophe, the Recession of 1920-21, President Coolidge's response was to do... pretty much nothing.
He knew what his successors did not: that the best form of government intervention was one that limited itself only to making conditions ripe for business growth, through low taxes, limited regulation, and as little meddling as possible.
That one-year recession was severe, caused by the overhang of spending and loose monetary policy from WWI. Yet it sorted itself out in record time and set the stage for nearly eight years of roaring economic growth.
The lessons of history are absolutely clear to anyone with the wit and will to pay attention to them. Trying to engineer one's way out of political and economic trouble does not work very well, because engineering is limited in its utility. Make no mistake, engineering is vitally important, for it is the practical, replicable, reliable expression of science in the real world. But it is ill-suited to dealing with highly unpredictable agents - such as human beings.