Is there significant overlap between originalism and political conservatism?
Given that it was founded by conservatives during Reagan's presidency, I think the association is more correlation than causation. However, I'd argue a progressive/regressive split (with originalists as the latter) is a cleaner fit. In an era where more and more moral questions were coming up that the Constitution never dreamed of, progressive judges were straying further and further from the actual words of the document they were supposed to be making decisions from, and were undertaking the very philosophical work of finding the underlying universal concept in order to apply it to these new circumstances.
Originalism was a push back against this movement, with the stricter originalists hewing to the standard of Original Intent, basically what the people that wrote the law were trying to say, and the less-strict originalists hewing to the standard of Original Meaning, focusing on what a reasonable person of the time and place where these laws were written would think they meant.
Seeing as we can't know with absolute certainty what the Founders would have thought of gay rights, internet privacy, or Muslim presence within the United States, the originalist thinks of himself more as an archivist or computer than a judge, and throws those sorts of questions out as outside of scope, essentially requiring Congress to be the final arbiters of change over time.
You can see how this would be appealing to conservatives, as it requires Congress to be on record for every change in the US Government and its laws, with an end result of fewer laws and checks-and-balances slowing progressive agendas. However, it doesn't require conservatism, just a willingness to take the subjectivity out of interpretation of the law.
Originalism says that we should use the constitution as written. Interpretation should only change from the original intent or meaning via the amendment processes included in the constitution itself. Originalism contrasts with the living constitution concept, where the constitution's interpretation should change over time.
Conservatives are people who prefer the traditional ways of doing things.
It should be obvious that conservatives have more to gain from originalism than do liberals. Originalism offers a return to previous interpretations, what we might call the traditional interpretations. Conservatives prefer the traditional. This makes conservatism and originalism correlated. In general, the same people believe both.
It is possible to believe in originalism and not be a conservative. For example, Cass Sunstein believes that Roe v. Wade was wrongly decided. But he also believes that abortion should be legal. Sunstein describes his legal philosophy as minimalism rather than originalism, but he is more in that vein than many.
Liberals tend to prefer living constitutionalism, which allows for a pragmatic interpretation where the justice votes for the best policy result or an argument where the solution is to try to reflect the decision that the original writers would have made if they had grown up with modern cultural referents. This allows for an organic growth in what the constitution covers without requiring the high level of consensus demanded to amend the constitution.
Originalism tends to slow down change, as it favors traditional outcomes. Living constitutionalism accelerates change, as it makes changes before they receive consensus support. Such changes may then receive consensus support. Or in some cases they may harden the opposition. Desegregation is an example of a change that later received consensus support while abortion is an example where the opposition hardened.
Both interpretation methods include a branch that relies on intent. As such, both methods are subject to the interpreter's opinion shading the interpretation. This is because people tend to judge others based on their own beliefs. In psychology, this is called projection.
It is also worth noting that liberal lawyers will still make originalist arguments where it suits their purposes. For one, such an argument may convince conservative originalist judges. For another, the law is somewhat originalist in its basic tenets. It relies on precedent as being controlling in a common law country. In theory, originalism only breaks with precedent where an older precedent exists or where precedents conflict. Even an originalist like Antonin Scalia still believes in stare decisis, that precedents should not be overturned outside extraordinary circumstances.
A lawyer is more likely to get the desired result if arguments supporting all interpretation methods favor it. So lawyers will make pragmatist (good policy), classical intentionalist (this is how it was originally meant, modern intentionalist (this is how modern society sees it), textualist (this complies with how it was originally written), minimalist (makes the fewest changes to existing precedent), etc. arguments. Various portions of those arguments may resonate with different judges.
For all intents and purposes, yes
Originalism simply tries to interpret US Constitution same as those who wrote it. Language of US Constitution is somewhat archaic, and full of legal technical terms difficult to understand by average educated common man. This was, and still is, exploited by left side of political spectrum to push for things completely alien to Founding Fathers and latter to those who wrote Amendments. Examples for this are abundant : overreaching federal government, killing of unborn (abortion), homosexual agenda, various "protected classes" , attempts to take away right to bear arms etc ...
Originalism moves in two directions : 1. to interpret text of US Constitution according to linguistic and legal norms that existed in the time of its creation (for example relation to English Common Law ) 2. to interpret "spirit" of Constitution by taking account what was assumed by Founding Fathers as universal knowledge that does not need to be codified. For example, there is no doubt that Founding Fathers considered marriage as a union between man and woman, and not as two men, two women, or three men, women and goat . They simply never considered they would have to explain this in the Constitution, or any other act, same as they didn't explain that the sky is blue and water wet.
Considering that US conservatism tries to conserve Republic and noblest American values, as they were originally intended, originalism and conservatism are for the most part correlated and do not exist one without other. Originalism explains the roots of US Republic , and conservatism act as a political movement to preserve those roots.