By a 'technocratic conception of politics,' (recall) I mean to capture the following three features of an enduring image of politics present in (social) science: first, it is characterized by the ideal that with social knowledge and its progress, substantial political disagreement can be eliminated. Here is a very striking instance of the claim from Milton Friedman's (1976) Nobel lecture: "Many countries around the world are today experiencing socially destructive inflation, abnormally high unemployment, misuse of economic resources, and, in some cases, the suppression of human freedom not because evil men deliberately sought to achieve these results, nor because of differences in values among their citizens, but because of erroneous judgments about the consequences of government measures: errors that at least in principle are capable of being corrected by the progress of positive economic science." The context of the passage is the furor surrounding his association with the so-called 'Chicago Boys' in Chile and the assassination of his Chilean critic Orlando Letelier (recall).
In particular, second, this ideal of conflict-free politics presupposes (as is clear from the quoted passage in Friedman's Nobel lecture) considerable value-unanimity in society. So, for example, in a famous article, the Chicago-school economists, Stigler and Becker write, "one may usefully treat tastes as stable over time and similar among people;" establishing this point "is the central task of this essay." When value-unanimity is granted then ordinary welfare economics is possible as a kind of (social) engineering science (recall).
Third, the conception requires an image of science in which one of the central aims of policy scientists is to achieve consensus (or lack of disagreement). In modern economics this idea goes back at least to Sidgwick's (1887) Principles of Political Economy (recall; for some prehistory on Hume). It was a central feature of Lionel Robbins's influential methodological restatement (1932) of what economics is: "Surely, for the sake of securing what agreement we can in a world in which avoidable differences of opinion are all too common, it is worth while carefully delimiting those fields of enquiry where this kind of settlement is possible from those where it is not to be hoped for —it is worth while delimiting the neutral area of science from the more disputable area of moral and political philosophy." This image of science was made widely popular by Thomas Kuhn in Structure (1960), but via Talcott Parsons's Weberianism and others it was already well known in mid-twentieth century social science.
It is worth emphasizing that the expectation of consensus was by no means universal. Friedman's sometime co-author, Savage, insists in The Foundations of Statistics, that "we must be prepared to find reasoning inadequate to bring about complete agreement." (1954 :7; see also 3, 67ff.) But this view became a minority position (cf. Aumann).