Many (perhaps most) people view politics through the prism of their personal preferences, which they arbitrarily regard as "true," "right," "good," "beautiful," etc. People with different premises are summarily dismissed as "wrong," "bad," "selfish," "naive," "stupid," "bigoted," etc. The tendency of all such ideologues is to believe that if everyone were smart and decent, they would all hold essentially the same political beliefs, and we would consequently have a government based on the "correct" principles. Such is the world as imagined by individuals with agendas.
The problem with these agenda-based belief systems is that they don't altogether accord with the facts. It's not entirely selfishness or naivete, stupidity or bigotry that cause people to disagree on political subjects. According to social psychology (see Jonathan Haidt, The Righteous Mind), an individual's intrinsic wiring (i.e., their DNA) will, more often than not, predispose them to accepting certain political ideals at the expense of others. This doesn't mean that political convictions are entirely founded on DNA. Obviously, personal experiences, as well one's immediate peer group, can count for a great deal as well, particularly when people are young and impressionable. But hardwiring often counts for more in the long run.
In terms of practical outcome, what this means is that an individual's political convictions are more likely to be formed on the basis his own (perceived) interests and sentiments, and not on the basis of
"the facts" and/or "reason." Political allegiances tend to contain a fairly large non-rational component. And they tend to be rather rigid in the sense that, once formed, it's hard to change them through "rational" persuasion. Simply attempt to convert a "progressive" to "conservatism," or a "conservative" to "progressivism," and you will see how things stand. It's very difficult to get people to change their political ideals. Human beings can be very stubborn in that way.
The conclusion I wish to draw from this is the following: since many people cling to political ideals that are, at least in part, founded on aspects of their personality that is hard-wired, it's naive to believe that, in a democratic social order, any political ideology will become so dominant that it can pretty much do as it pleases, without fear of opposition. Human nature is not homogeneous. Not everyone has the same innate sentiments. Nor do they all have the same interests. For this reason, a democratic society will always be divided by various factions animated by opposing sentiments and interests. There can never be a complete unity on every important challenge or issue facing a nation or its political system. Consequently, a government, particularly in a democracy, is "an arrangement"; that is to say, it is not the consequence of any single person, or ideology, or consensus. It's rather the somewhat random outcome of various factions attempting to pursue their unique interests and satisfy their particular sentiments within the parameters of the political system. The actual government that results from this process rarely accords to anyone's political or ideological ideal.
Putting this another way, there is no such thing as "The People." Ideologues are fond of saying that "The People" want this set of policies or believe in that set of ideals. But this is all nonsense. There is no "The People." Instead, their are many different peoples with different emotions, sentiments, biases, interests all competing within the social order for influence, power, and "social preeminence." Out of this competition (i.e., the political process) emerges both the governing elite and their policies. This process is, of course, rather kludgy. It can't be counted on to create optimal solutions (even when, as now, they are so badly needed). Often the political process leads to policies that all but the most partisan commentators have to admit are blatantly dysfunctional.
For example, consider the national debt of the U.S. It stands at $19 trillion (and that's not counting all the unfunded, perhaps even unfundable mandates that are facing the U.S. in the future). How could the federal government allow the nation to reach such an untenable position? It's not in hardly anyone's interest to have so high a debt. It's not in the interest of most people on the right, because it almost invariably guarantees higher taxes and less money for the military; and it's not in the interest of most people on the left, because it will inevitably put a fiscal squeeze on social programs. Yet there it stands, all 19 trillion of it, and continuing to grow at an alarming rate.
Then we have the whole corporate welfare/crony capitalism cancer that's eating away at the productivity of the nation, to the detriment, mostly, of the middle class. Admittedly, there are people within the political and economic elite who benefit from this sort of thing. But most people outside these elites, regardless of their political ideology, don't benefit from it and, for the most part, are against it. And yet it persists despite any kind of political "will" to change it. Why is that? The huge political advantages which elites enjoy over the non-elites plays a big part in this. But it's also a consequence of the fact that are political system is a mere "arrangement," not a rational application of a given system or ideology.