"A Spirit Which Nourishes Freedom"

In Federalist Paper 37 James Madision presents the question:

                    "what is to retrain the House of Representatives from making legal
                    discrimination in favor of themselves and a particular class of society?  I
                    answer: the genius of the whole system; the nature of just and
                    constitutional laws; and above all, the vigilant and manly spirit which
                    actuates the people of America-a spirit which nourishes freedom, and in
                    return is nourished by it."