What exactly is the reaction of the political culture in the US and/or the public if confronted with an unusual combination of opinions? Are there precedents which are well-known in the public?
In my experience, lectures. E.g. you can't possibly believe that Donald Trump is more qualified to be president than Hillary Clinton!
The major problem in the United States is that there are always exactly two serious presidential candidates (Ross Perot showed signs of seriousness in 1992 but ultimately was an also-ran). So the nation has to make a choice between two combinations of opinions. Since 1912, the two candidates have been Democrats and Republicans (in 1912, former Republican Teddy Roosevelt came in second under the Progressive or Bull Moose party). Since 1848, no other party has won the presidency (with the arguable exception of Abraham Lincoln's Union party in 1864, but everyone understood that he was a Republican).
The end result is that the two parties determine the bundles of opinions and they do so mostly in competition with each other. The Democrats are the union workers party, so the Republicans are the small business party. The Republicans are pro-gun rights, so the Democrats are for gun control.
These coalitions shift over time though. Some examples:
- In 1860, Democrats were the party of slavery. Modernly, most black or African-American (two different names, each problematic in their own way, but for the same distinction) vote for Democrats. This can be traced in part to Republican Herbert Hoover's pursuit of the white South in 1928. But also to Democrats' pursuit of the poor in general.
- In 1976, Democrats were the pro-life party, against abortion and the death penalty. In 1980, Ronald Reagan ran as pro-life, against abortion. Since then, Democrats have become the pro-choice party, favoring abortion rights. Democrats remain the anti-death penalty party with Republicans pro-death penalty.
- Republicans like Susan B. Anthony were the suffragettes (for recognition of women's right to vote). Modernly women's rights advocates are generally Democrats.
- Democrat John F. Kennedy favored a supply-side tax cut before his death (it passed after he died). That position is now identified with Republican Ronald Reagan. Reagan is also noteworthy for having claimed that the Democratic party left him, causing him to switch to being a Republican.
- Democrats used to be a rural and urban party. Now rural voters are overwhelmingly Republican.
- Republicans have traditionally been for free trade and against trade restraints like tariffs. Yet current president Donald Trump is noted for his support for protectionism. Is this the start of a shift? It's unclear if Trump is an outlier or the first of a trend, the way Reagan was with the pro-life position.
The truth is that individual voters in the US do have different bundles of views. However, the coalitions for president are often more stable and driven by primary politics. We can see different results in the legislature:
- Senator Bob Casey, Jr. is nominally pro-life, favoring a constitutional amendment opposing abortion. However, on procedural grounds, he tends to vote pro-choice on Supreme Court justices and spending issues (he is against abortions but for the government paying for them as long as they are legal).
- Senator Susan Collins is pro-choice but votes in favor of Republican judicial nominees, who are generally pro-life.
- Senator Rand Paul has decidedly un-Republican views on things like drone strikes, military interventions, and the Patriot Act.
- Senator Joe Manchin is a pro-gun rights Democrat as have been several other "red" state Democrats.
I would also count Heidi Heitkamp, Joe Donnelly, and Claire McCaskill as examples of Democrats with heterodox views or at least voting patterns.
A lot of what happens is that people find themselves having to justify the positions of their presidential candidates. This results in a lot of people saying that they either disagree with that particular position but agree overall or with people defending positions that they don't really hold personally. It's not so horrible that such and such took this position on abortion. The arguments in favor are... Argue the pros of a position for long enough, and you tend to develop a certain amount of personal support.
The other issue is that some people may not have strong feelings one way or the other. But they get stuck in discussions defending their candidate's positions on things they find unimportant. But this too leads to them eventually taking the candidate's positions.
For example, since Reagan, the three pillars of the Republican party are the economic, moral, and international. So someone can care about economic issues like low taxes or minimal regulation. Or someone can care about moral issues like abortion or law enforcement. Or someone can care about a strong defense and negotiating from a position of power. Those pillars are not connected by anything but the party. However, the party has built itself around them.
The Republican party's position on religious freedom rises from its position on moral issues. The same people who are pro-life care deeply about religious freedom from what they consider to be anti-moral positions, e.g. same sex marriage.
Similarly, the Republican party's position on trade comes from two of the pillars: economic and international. The economic argument is that people should be free to make their own purchase decisions. The international argument is that we should be engaged internationally, and trade is our best foot forward.
Anyway, my point is that the US system is a result of the US system. The US has a first-past-the-post presidential election. Duverger's law says that this will tend to produce two dominant political parties, the winner and the loser. I.e. that members of losing parties will tend to make common cause with either the winner or with other losing parties until there are only two parties.
Reinforcing this is the primary system. In primaries, the hard core Democrats and Republicans are split from each other. And in many, only registered party members are allowed to vote. This can lead to two extreme candidates being selected, as the extreme candidates have the most support from the party base. So compromise candidates may not make it to the general election, even if they would receive more support.
Another reason is the increasing nationalization of the vote. Many Southern Democrats lost in 2010, 2012, and 2014 because everyone knew they were going to support Nancy Pelosi for Speaker of the House. This is pretty advanced in the US.