Why do so-called conservatives (Republicans) in the United States have liberal beliefs (and vice versa)?

The terms conservative and liberal have a lot of meanings, with small government vs. big government being only one aspect of it. There is also tradition vs. progress, moral regulation vs. financial regulation, and a belief in objective morality vs. in subjective morality. These meanings also ebb and flow over time and geography. I'm going to be referring to the modern American ideologies; Goldwater may disagree with some of my descriptions of conservative thought. There's a longstanding tradition of believing that homosexual relationships are somehow inferior to heterosexual ones, rooted both in the most common religions in the USA and in the social norms of its national history. Liberals (or, more properly speaking, progressives) see it as a social improvement to change this past trend into a more accepting and tolerant one; conservatives see it is an experiment in novelty that unnecessarily risks the stability of the country. Many conservatives consider the burden of proof to rest on the progressives; let them who are advocating social reform prove the reform's value before a generally stable and healthy society is reformed, they say. Before you alter something so intrinsic and fundamental to our culture as marriage, conservatives may say, convince us that our culture will not face unexpected negative consequences. Progressives think the burden of proof rests on the conservatives to prove negative consequences will result. Progressive theory holds that it will be an improvement, they say, so show us where reality contradicts the theory. Progressives will also point out that there is no evidence in either direction until a policy is implemented and tried. It is better, say progressives, to try, fail, and try again than not to try at all. It is better, say conservatives, to disregard foolish ideas or wildly innovative experiments than to try and fail and try and fail repeatedly. Conservatives often prefer very small, incremental changes to broad, sweeping reforms. This, they believe, maximizes cultural stability and minimizes the unexpected consequences of new policies. Libertarians, conservatives, and liberals agree on this principle: humans are not commodities, and morally cannot be allowed to become commodities. Individual choice and individual rights have their limits, and that's one such limit. However, conservatives apply this principle more broadly than the other groups, especially as it relates to consensual individual behavior. All three groups oppose slavery on that basis, but many conservatives also oppose prostitution, abortion, embryonic stem cell research, and a free market in organs for transplants on the basis that they seem to be treating humans as commodities to be bought, sold, and discarded without respect to human dignity. The quick progressive response to this attitude is to accuse conservatives of respecting the dignity of the fetus but not the woman. Progressives see the woman as clearly, tangibly, fully human and the fetus as not, and thus the moral judgement sides with her every time; that, in their minds, is the proper way to respect both sides. Conservatives believe the proper way to respect both sides is to weigh the intangibly moral costs as well as the tangible, material costs. A society that disposes of its young, innocent children to protect its adults is, in the conservative mind, a corrupt society that is slowly poisoning itself. Conservatives believe that such an outcome must be weighed in addition to the dilemma of child's rights vs. mother's rights. The implied conservative accusation of the mother's guilt ranges from targeted and disgraceful slut-shaming to more tactful arguments such as "We're all sinners by the time we reach adulthood, but the unborn have not yet had an opportunity to sin. We ought not punish them for behavior they have not yet committed." Some few progressives will argue that the life of an unwanted child is fundamentally a life of suffering, and that abortion spares them of that suffering. I, as a conservative, find this view morally abhorrent. We all suffer in life, but that doesn't make our elimination morally desirable. If a life that includes suffering is not deemed worthwhile, there's no reason for any human to live. Ultimately, neither major party in America holds one and only one political principle absolutely sacrosanct above all others. Not small government, not individual rights, not anything. Libertarians do that, choose a single principle and elevate it above all others. Perhaps that is why they remain a marginal party. Many libertarians frame their characterizations of the major parties around the idea that complexity, nuance, and the weighing of priorities against each other (ie, thought) as the kind of logical gymnastics and contortions inherent to rationalizations of self-contradictory nonsense views. The major parties see Libertarians as overly strict ideologues with no sense of compromise or pragmatism. Thus, they each see the others as worthless politicians. Disclosure: I'm a conservative Republican.

So many answers: One is because Liberal has a variety of meanings and originally (and still does) meant free-trade, liberty, hands-off economy, etc. Conservative can mean "traditionalist" or maybe sometimes "yesteryear's liberal."   Another answer is that you're splitting things that shouldn't be split into a false dichotomy. You're conflating Conservative with Republican. Not always the case and doesn't have to be. Political parties are coalitions of people with different ideologies. Often we think of political parties as ideologies but Rand Paul and John McCain are more ideologically different than either one is to our President. I think you want to read this: http://www.theatlantic.com/politics/archive/2014/06/the-left-right-political-spectrum-is-bogus/373139/

There are conservative and liberal wings of both parties. I'd find it hard to believe that anyone's opinion on every issue is represented by one of 2 choices. That's why I find the pattern of calling Moderate republicans RINOS surprising and counterproductive. Democrats due lean left on a lot of issues, but it hasn't always been the case. As for the question details: Republicans do plenty of big government things as do Democrats. It's just that Democrats tend to do  big government things in the past decades that give money to poor people.  Republicans have been claiming to be small government since I've been alive and able to read ( I'm 44) that's not the same thing as actually being small government. Military spending is pretty big government. Since JFK became our first ( and only to date) Catholic President Democrats have been pretty dedicated to having a firm wall up between religion and state. In the end, there are only 2 political parties.. Both pretty flawed IMHO.

I'm very on the conservative side but in many ways I am very liberal when compared to the typical Republican image.  Label me as a Libertarian.  Those in that group generally believe in a small government along with letting people do their own thing to a point where someone else is in danger.

The issue with abortion is the rights of the unborn baby vs. the rights of the mother. It is dishonest to present the abortion issue as solely a women's rights issue.  Most laws usually deal with the conflicting rights of individuals  where the two parties have conflicting interests. It is for that reason, I don't see abortion as  right wing or left wing topic or a topic for smaller government. The purpose of government is to resolve conflicts between two parties.

Originally, the two parties were as you imagine them to be- the Republicans were the Liberals, and believed in individual human rights, and the Democrats were the conservatives, and believed that governments and groups can overrule individual rights. The big issue was Slavery. Lincoln created the Republican Platform on the concept that slavery should be abolished, while the Democrats, who were mostly southerners, believed their economy was dependent on slavery. That was how it was, Liberal Republicans and Conservative Democrats, until 1948. The Democratic Party supported the Civil Rights movement, and that got the Southern Conservative Democrats so ticked off they formed their own party- the Dixiecrats. http://en.wikipedia.org/wiki/United_States_presidential_election,_1948 Then in 1968, along came Richard Nixon. Audience, you can boo now, because he is the villain of the story. Nixon devised the "Southern Strategy". The Republican party openly embraced Racism and Evangelical Christianity to win the Dixiecrats over, and it worked. The formerly Democratic South turned Republican, And the Democrat North, turned from the Republican party in horror and became Democrats- who were Liberal since the Dixiecrats left. By the Reagan administration, the transition was complete. http://en.wikipedia.org/wiki/Southern_strategy That is why you will find poor white southern Christian men voting for the rich to get richer and the poor to get poorer- because of god, gays, guns, and blacks. To this day it is amazing how you will find Republicans in complete denial of the racism in their party, when the Republican Party even ADMITTED it. http://www.washingtonpost.com/wp-dyn/content/article/2005/07/13/AR2005071302342.html As for women's rights, gay rights, and the rights of non-Christians, those issues go hand in had with racism. All forms of bigotry are the same- those people over there are inferior, and must be put in their place. So, along with embracing racism, it was only natural for the GOP to embrace sexism, homophobia, and xenophobia as well. Now, the GOP is is a quandary- the bulk of the population is against racism, so much so we elected a black president, so the GOP has to abandon it. But if they do, they will loose those poor southern whites who would otherwise not vote against their own economic interests.

Liberals have come to rely on rules, created by democratic processes and enforced by government, as a way of ensuring equal rights.  This is not the first choice, but rather a position of desperation due to frustration.  Conservatives block efforts at liberalization at every step, and have proven adept at manipulation of education and the media to keep outdated prejudices and the redistribution of wealth from the working class to the ultra wealthy.  (the question originally indicated a preference for libertarian ideals, but that was removed. The following comments are in response to that original position)    Libertarians tend to support the idea of a "keeping all their own earnings" but not paying all their obligations to the next generation.  That makes it a bankrupt ideology.  If you truly believe that libertarianism works, point to an existing, successful government, anywhere in the world, that exhibits those traits while maintaining a reasonable standard of living for its people. You cannot.  It does not exist.  Libertarianism is less feasible than communism was. The entire concept of "big" vs. "small" government is hogwash.  We should be talking about "effective shared services with a minimum of interference with reasonable liberties, as long as you do not cause harm to others." In that context, women have the right to abortions and gays have the right to marry and the NSA stops spying on our people, and government builds roads and provides free, high quality, public education, and we unite to provide for a common defense. I'm a liberal.

Pay attention to what Conservatives really say and do (Biblical: "Know them by their deeds").  In "The Tea Party: America Upended " I  discussed the pattern of rhetoric over substance which will bring down Washington & America. [http://www.amazon.com/Tea-Party-America-Upended/dp/1494996499] Republicans -- specifically those gravitating to The Tea Party segment -- actually want more government.  What they don't want is a government which helps the average person or supports the doctrines that their Christian evangelical element of the Tea Movement should be demanding (but is actively opposing). True Conservative Beliefs actually help the little guy -- which is why the rhetoric is so powerful ... and why the GOP profits because people are too dense to look at the deeds.

Maybe we need to add the term "progressive" into the conversation.  Left and right progressives want our money and want control.  The left want to loot our money and spend it on social programs a'la welfare and food stamps.  The right want to loot our money and use it on nation building in other countries.