At Liberty Law Blog, Richard Samuelson: Entropy in the Executive. From the conclusion:
It is, however, an open question whether a government as big as as ours can at this point stay a limited constitutional government. Must contemporary “big government,” to use our shorthand term for it, be arbitrary government? Madison worried that it would be, as he noted in a passage I quoted in this space recently. It bears re-quoting in the current context:
In proportion as the objects of legislative care might be multiplied, would the time allowed for each be diminished, and the difficulty of providing uniform and particular regulations for all be increased. From these sources would necessarily ensue a greater latitude to the agency of that department which is always in existence, and which could best mould regulations of a general nature so as to suit them to the diversity of particular situations. And it is in this latitude, as a supplement to the deficiency of the laws, that the degree of Executive prerogative materially consists.
Madison may not have been entirely correct. It might be possible, in some ways, to expand the job of government in a manner consistent with the separation of powers. But that line probably does not go all that far. There is one particular concern to keep in mind. Human beings are creatures of habit, as are our politicians. An executive that grows accustomed to having a great deal of discretion in writing and implementing the laws that Congress passes will, almost certainly, come to think his job is to exercise discretion in general, even in cases where the law is quite clear or where there is no law giving him any authority to act.
Given that the kind of person who is likely to become President is not likely to be the kind of person who likes to think of himself as the employee of anyone, much less of the common people of the United States, the growth of administrative discretion is a grave danger to the separation of power and hence to the cause of republican self-government.