Students of the exercise of emergency powers in the American governmental system have taken note in recent years of an obviously widening gap between what presidents assert they can do in emergencies and what congressional and court critics of presidents, and many serious scholars, say are the constitutional and statutory limits on executive emergency powers. The perceived widening gap is something new, though Americans seem to have accustomed themselves to it quickly enough. In the shadow of what has come to be called the era of the imperial Presidency, some say that one extreme tendency demands a compensating counterbalancing tendency toward the opposite extreme. Indeed, it is now widely believed that what had been an accelerating quantitative increase in presidential power has largely resulted in a qualitative transformation that threatens the continuance of “free government,” requiring intensified criticism of presidential practice as well as, perhaps, a temporary exercise of emergency powers by other branches of our government to restore the traditional balance of separated powers.

Administrative law in the United States during the last half century has been dominated by three major themes: (1) the extent to which legislative authority may be delegated to administrative agencies, (2) judicial review of legislative action, and (3) analysis of the formal aspects of agency procedures. At the core of this traditional approach to administrative law—defining its purpose—is the problem of the legitimacy of public administration. Specifically, the issue, to traditionalists, is how far administrative agencies can go before they impinge on the rights of private citizens.

In 1962 Sam Bass Warner, Jr., published an important book about suburbanization in late nineteenth-century Boston. Like most influential books, it was timely in its subject, and Warner's scholarly study might be supposed to have built upon the interest that was being generated by numerous popular analyses of contemporary suburbanization and suburban life in post—World War II America. One can indeed find in Streetcar Suburbs the same fundamental preoccupation with the shallowness of communal life and similar diagnoses of the sprawl of single-family homes in homogeneous and militantly residential areas on the periphery of the city, as one finds in say, William H. Whyte's 1956 critique, The Organization Man.' Yet Warner's book was not part of, and did not initiate, a new genre of historical suburban studies. Instead, it served as one of the essential founding texts of what came to be known as the “new urban history”—a large number of scholarly attempts to examine the character and structure of life at the center of the developing big cities of industrializing America. Not the “crabgrass frontier” but the “urban frontier” defined the territory of historical adventure during the 1960s. The metaphor is not, and was not then, entirely an academic one. In 1961 the new President of the United States had called for a “new frontier” of public initiative, and planner Charles Abrams helped his immediate successor expand and locate that initiative with his book, The City Is the Frontier. Without entirely losing interest in the suburbs, scholars, policymakers, and citizens of various kinds suddenly realized the importance of understanding the city and its history.