"Politics is the art of the possible" . This piece of folk wisdom comes from Otto von Bismarck and reads in full “Politics is the art of the possible, the attainable — the art of the next best” (courtesy of Wikipedia).
I'm not sure that the complete quote adds much to the short version, though I like 'the art of the next best'. Like all aphorisms it contains a powerful grain of truth but is far from the whole story..
Modern, Western democratic politics may be somewhat cynically viewed as an elaborate public soap opera conducted according to written and unwritten rules. The precise nature of these rules, and the institutions which monitor and enforce them, vary between democratic nations and over time but, nominally at least, the central purpose is to give meaningful expression to the popular will.
A long, bloody and intellectually rich history has converged on a set of democratic institutions which are designed to accomplish two important objectives. The first is the Rule of Law, namely, the norms and institutions which preserve the democratic system itself against erosion by personal ambition and tribal or ideological passions. The second is Freedom of Expression which, together with The Media, is intended to extract and scrutinise the underlying values, motivations and contending ideas behind the political theatre so that rational and optimal choices can be reached by the broad public.
In other words, within this framework the ordinary citizen is expected to decide which of the parties participating in the soap opera will best serve their interests. I have used the unflattering term 'soap opera' since it captures the component of deceit and intrigue which is an inescapable part of politics, but also because the media for various reasons of its own has an interest in presenting political issues in theatrical terms - as an on-going, larger-than-life epic which taps into the public's own moral universe of values and emotions.
But, additionally, there is an inherent contradiction between the idea that the democratic process allows the broader public to converge on the set of policies and politicians which will best serve the common interest and the fact that human cognition is inherently emotional and tribal in nature and can thus be steered into various dead-ends which best serve the interest of one or other elite.