In "The Degradation of Citizenship" Deneen spells out the specific ways that popular control has been deliberately stymied in the American liberal order. One aspect of this was a trend from the early 1900s to seek to base government policy not on the "whims" of the electorate but to implement "rational and objectively sound public policy" formulated by expert administrators. Deneen writes:
Major figures in the discipline like Woodrow Wilson sought to advance the scientific study of politics in the early years of the twentieth century, laying the groundwork for the rise of social scientific methodology as the necessary replacement of value-laden policy. Early figures in the institution of political science...called for the scientific study of politics as the prerequisite for objective public policy. "Nothing is more likely to lead astray," wrote A. Gordon Dewey of Columbia University, "than the injection of moral considerations into essentially non-moral, factual investigation." (p.160)
But what would be the measure of "objectively" good policy shorn of moral considerations? Deneen answers as follows:
Classical and progressive liberals shared not only the ambition of constraining democratic practice and active citizenship but a substantive vision of what constituted "good policy". Good policy for the Founders and progressive alike were those that promoted the economic and political strength of the American republic and the attendant expansion of power in its private and public forms. Liberalism sought not the taming and disciplining of power, along with the cultivation of attendant public and private virtues like frugality and temperance, but institutional forms of harnessing power toward the ends of national might, energy and dynamism. (pp.166-67)
Deneen rolls together the aims of liberal modernity in the following passage:
For all their differences, what is strikingly similar about the liberal thinkers of the Founding Era and leading thinkers of the Progressive Era were similar efforts to increase the "orbit" or scope of the national government concomitant with increases in the scale of the American economic order. Only in the backdrop of such assumptions about the basic aims of politics could there be any base presupposition in advance of the existence of "good policy" - and that policy tended to be whatever increased national wealth and power. In this sense - again, for all their differences - the Progressives were as much heirs as the Founders to the modern project of seeing politics as the means of mastering nature, expanding national power, and liberating the individual from interpersonal bonds and obligations, including those entailed by active democratic citizenship. (p.172)
Something along similar lines was happening in Australia at this time. If you look at the decision taken in the early 1940s to end Anglo-Australia, you find the same themes. First, the decision was kept from the general public - it was not subject to democratic choice. Instead, the key discussions took place within an "Inter-Departmental Committee" with much influence from the work of political scientists like W.D. Forsyth who used population data and labour force statistics to recommend policies that promoted "development". The politician most responsible for the shift in policy, Arthur Calwell, was determined to move toward an ethnically heterogeneous society (though not at this stage a racially heterogeneous one).
The key point to take away from this is that traditionalists need to take care with calls to national greatness. In the context of liberal politics, this may not advance the existence of an historic people, their culture and embedded way of life. This aim of conserving an existing people is not what has been understood by "national greatness" within the liberal order; instead, such greatness is measured by economic growth and the attainment of political power which then becomes the measure of good public policy. Immigration policy, for instance, is considered sound within this liberal order to the degree that it advances economic growth ("development") and political power (and liberates individuals from interpersonal bonds), rather than to the degree that it promotes the continuity of the life of a particular people.