Actual randomness is much more streaky than human intuition would predict. In an NPR interview on NPR, Professor Andrew Gelman from Columbia gave the classic illustration from Stats 101. Gelman splits his class into two groups and asks both to record 100 flips of a coin on the blackboard while he is out of the room. One group flips an actual coin 100 times, the other is asked to simply imagine a hypothetical coin flip. The professor returns to two lists of letters, each a "random" series of "h"s and "t"s:
Professor GELMAN: Right. A real sequence of coin flips is likely to have a long run of heads or tails. You're more likely than not to see a run of seven straight heads or seven straight tails. The fake sequence, they tend to alternate too much between heads and tails, so I can immediately see the fake one looks too random and the real one looks like something strange went on.What are the implications for our current state of affairs? Maybe the streaky nature of random variation can explain how John Boehner and 231 of his closest Republican friends managed to engineer the worst Constitutional Crisis since the Civil War, not by design, but by ACCIDENT!
Consider the IQ of these members, knowing what we know about genuinely random coin flips (I'm mixing some concepts a little here to make a point). Sure, over 223 years of Congressional history the individual IQs of the conservative faction in Congress probably sort into the same bell curve that charts the population at large. But because real randomness is sometimes streaky, elections will occasionally stock the GOP caucus with an absurdly high percentage of low grade morons.
This is one of the ways that pure chance intrudes into history: the disconnect between the skills a leader needs to be elected (or to triumph over cousins vying to be king, etc.) and the skills a leader needs to enact good policy. Ending up with a good medieval king seems to have been pure luck.
Modern democracies have a bit more success, but electoral success is still far from a guarantee of policy competence. Moreover, the skills needed once in office vary based on contingencies that impossible to predict at election time.
For example, Abraham Lincoln's greatness was due not just to things that had nothing to do with his political success, but also to things that, before the Civil War, weren't yet understood as things a person could be good at! Millions of Americans, mostly whites in the South, would be much worse off today if he these contingent facts had been otherwise.
Today, the rise of ideology on the right has generated a situation where the competency of our politicians is crucial. Successful navigation of the jam we are in requires skills that elections do not select for. Did fickle Fortune give us GOP Congressmen with the needed qualities? No.
Why not? Maybe the last few elections, thanks to pure random variation, sent 232 borderline retarded individuals to Congress.
Update: the developmentally disabled caucus does not understand the debt ceiling. Ted Yoho: We Must Destroy the World In Order to Save It
Good updated list of moron moments: Lawmakers who struggle with the basics
1. In reality, intelligence and choosing to run for office as a Republican are probably not independent variables.