The metaphor of a neutral umpire or referee is never far from the surface of any public policy debate. The politically immunizing aphorism, "I just call'em like I see'em," concisely conceals and perpetuates an assumption that is both ubiquitous in its practical adherence AND demonstrably impossible to achieve. Neat trick, right?Political actors of all kinds, including judges, judicial nominees,and yes, even voters, operate on the assumption (whether they believe it or not)that objective truth, objective right and wrong, exist and "should" control in questions of law and policy. The only arena where this "common sense" is thought not to pertain is "politics." Indeed, to be political is effectively to pursue subjective goals, like "subjecting" people to your self interested definitions of reality in order to shape public policies in your own favor. From this viewpoint, there are right and wrong answers to EVERY important question and if you are not supporting objectively true answers, you are engaging in "politics." By implication, if you are supporting objective truths, then you are NOT engaging in "politics," which, when defined in this way, is literally fraudulent.
Does this mean that political activity is always subjective? Yes. Does it mean that political behavior is always fraudulent? No, but it is always politically useful to equate the views of opponents as "political" because it implies that your own (political)cause is a non-political pursuit of the truth, the facts, or what's right, and that you will never let "politics" [i.e. the pursuit of narrow self interest] influence your work as a public policy maker.
Americans have always accepted and even celebrated political "horse trading" when the stakes are merely materialistic, or commercial. In other words, when different interests, none of which is inconsistent with the general interest (as defined by a broad consensus on objective truths), compete for power (or market share) the result will be a competitive political/commercial economy. The problem arises when political/commercial competitors seek to promote or impose different definitions/ interpretations of objective reality, or "the facts," in an effort to increase their own influence/ market share. Politics then, moves from the consensual realm of material exchange among equals to the existential and epistemological realm where no definition or interpretation (however popular) is indisputable. This frustrating situation is the inevitable result of increasing competition in politics and business. When you are losing, change the rules, norms, or expectations. If your goals don't fit the process, redefine the process to fit your goals. In other words, re-frame the competition in ways that will bring the perception of "reality" and of the "facts" more in line with your interests.
American liberals and conservatives are not shy about employing science and religion, respectively, in an effort to frame or define reality (understood as objective truth) in ideologically friendly ways. Science and religion are useful props precisely because they have credibility as non-political, truth seeking arenas. Nonetheless, the left and right in America assumed by most Americans to be engaged in a narrow, self serving campaign to impose their own subjective definitions of reality on the American people, contributing to the conventional understanding of partisan viewpoints as subjective by definition as well as an understanding of "actual" reality as having no partisan biases and as politically neutral, objectively verifiable, universal truth[s]. This means that "truth" can only be discovered by disinterested and dispassionate inquiry.
In democratic politics then, partisanship and politics, understood as entirely subjective, are fair game in political arenas like elections where voters choose like-minded folks to govern, but should have no place in the actual decision making in government or any other venue where it is important to make the "right" decisions for all interested parties. In government, the right decisions are the one's best for all citizens, no matter who they voted for, right? Therefore, politics should never be allowed to intrude on policy making, administration, or adjudication. These activities must be conducted according to THE merits (you know, those universal politically neutral standards for measuring the relative quality of competing policy ideas)!
If there are no such standards, how's a poor lone voter supposed to judge the performance of office holders and the content of public policy in a democracy? It would be bedlam! Hopeless relativism! dogs and cats living together! Right!?!?