The phrase “The Koch Brothers” has become a shorthand for the insidious spread of radical right-wing power in America. But even those of us who devoured Jane Mayer’s book “Dark Money,” as well as the work of other journalists who illuminated the reach of billionaires Charles and the recently deceased David Koch, including their massive network of conservative and libertarian Political Action Committees and the lobbying efforts of those PACs, might have only a glimmer of an idea of the size and scope of Koch Industries. The business is headed by Charles (David was a shareholder, but not involved in day-to-day affairs), and it’s what gave the brothers their money and influence.