He is renominated in case he has served his party well, or in case no one else who wants the job has in the meantime served it better.

He is reelected in case his party happens to have kept public confidence.

Departmental chiefs can be made responsible for their work only by being subordinated to a chief executive whose duty it is to keep his eye on his subordinates and who is accountable to the people for the efficient conduct of all the administrative offices.

The former, consequently, must be selected by appointment, they must be installed in office for an indefinite period, and they must be subject to removal by the chief executive.

Those are terms upon which all private employees serve; and on no other terms will equally efficient results be obtained from public officials.
Under a democratic political system there is, of course, no way of absolutely guaranteeing that any method of administrative organization, however excellent in itself, will accomplish the desired and the desirable result.