It is customary to refer to political/economic systems as being on a spectrum, with communism on the far left, liberalism in the centre and fascism on the far right. The political spectrum is a powerful metaphor, and we are all deep in the habit of using it, but there are problems with its use as a model for reality. For one thing, it tends to encourage the idea of a 'slippery slope' of political structures; hence, today we introduce 'socialist' health care, tomorrow we line up to apply for a Lada.
This is because of the human tendency to mistake descriptive metaphors for predictive models. Yes, politics can be understood as being like a spectrum, in the sense that you can 'line up' the different political positions such that each one represents an incremental change from the one next to it, but this is where the similarity ends. Unfortunately, as soon as public policy is perceived as shifting in a certain direction along the continuum, people whose views lie in the opposite direction may feel that the movement is the beginning of a trend. Sometimes, this perception is quite correct; it is unquestionable that politics moves in trends, swinging slowly this way and that, as if tugged between the two ideologies on either end of the spectrum. However, the important phrase in the last sentence is 'as if'. A pragmatic government which raises the minimum wage and helps fund community projects is not being secretly run by a bunch of communists looking for a back door to world domination. But when politics is understood as a spectrum, then every step to the left is a step towards the Great Communist Scourge waiting out at the edge. Similarly, every step to the right is one step closer to Nazi Germany.
Needless to say, this kind of thinking does not encourage sensible discourse.
At its worst, this kind of thinking can be manipulated to stop very pragmatic and humane reforms from gaining currency, even among the people who would benefit most. Take health care. By every imaginable measure, a publicly funded, not-for-profit health care system is far better than a private, for-profit system. More people get better, more consistent, and fairer care at much greater efficiency and for a lot less money than under a private system. However, America, the richest country in the world, still has private health care, 40 million people with no insurance, tremendous administrative overheads, obscene profits and wildly uneven services. There are all sorts of reasons for this, but at least part of the problem is that people have had it rammed down their heads since time immemorial that no red-blooded American would allow some Socialist scheme to take away his God-given right to pay top dollar for the best health care that money can buy.