Textualism is a school of legal interprtation. It may be contrasted with Intentionalism (and the specialized version of intentionalism known as Oraginal Intent theory), with Strict Constructionism and the Living document or Living tree school. The latter is generally applied only to written constitutions and other important legal documents that have survived with relatively limited change over a relatively long time, primarily the US Federal Constitution.
A textualist generally accords no weight to the "intention" of the legislature (or other body) which passed a regulation, law, or constitution, and is therefore also not interested in "legislative history (records of debates over the passage, drafts that did not pass, and statements or reports by individuals or committees or staff on the intended purpose or effect of a law).
A textualist looks at the meaning of the whole document, as it would have been understood by a person knowledgeable in the law at the time the law was passed (or constitution or treaty was ratified). A textualist will consult specialist sources for the meaning of jargon or terms off art at the time of passage, and may consult dictionaries or other sources to determine the ordinary meaning of non-specialist terms at the time of passage. A textualist is not interested in the modern meaning of words, or of the document as a whole, but only in the meaning as it was at the time of passage. A textualist considers that the meaning of the document is fixed at that point, unless it is amended or altered later. A textualist normally considers a document as a whole, not an individual word or clause except in the context of the rest of the document.
Textualism is a formalist theory. It is sometimes known as original meaning theory.
US Supreme court Justice Scalia described himself as a textualist, and was perhaps the most well-known textualist in the US during his term on the Court.
In the case of K-Mart v. Cartier, 486 U.S. 281, 319 (1988) Justice Scalia wrote:
The statute excludes only merchandise "of foreign manufacture," which the majority says might mean "manufactured by a foreigner" rather than "manufactured in a foreign country." I think not. Words, like syllables, acquire meaning not in isolation but within their context. While looking up the separate word "foreign" in a dictionary might produce the reading the majority suggests, that approach would also interpret the phrase "I have a foreign object in my eye" as referring, perhaps, to something from Italy. The phrase "of foreign manufacture" is a common usage, well understood to mean "manufactured abroad."
US Justice Robert Jackson used the term "textualism" in the 1952 case Youngstown Sheet & Tube Co. v. Sawyer. That was the first use of the term in a US Supreme Court opinion.
A follower of Original Intent theory looks at what the authors of the document (the legislature for ordinary laws, the convention for the US Constitution) indented to achieve, what their purpose was. Such a person then attempts to interpret the document to achieve that purpose, regardless of the exact meaning assigned at the time of passage. Textualists deny that there is such a thing as the intent, because each legislator or delegate may have had a different intent, and we often cannot know what the intent of any one of them was, anyway. Original Intent is an interpretivist theory
A strict constructionist construes the powers of the government narrowly, as a rule. The term has been, in the US, applied primarily to judges of a conservative bent, and has become almost a synonym for "conservative judge". Few Judges so describe themselves.
In his lecture A Matter of Interpretation (Princeton 1998) Justice Scalia wrote:
The difference between textualism and strict constructionism can be seen in a statutory case my Court decided last term. The statute at issue provided for an increased jail term if, "during and in relation to ... [a] drug trafficking crime," the defendant "uses ... a firearm." The defendant in this case had sought to purchase a quantity of cocaine; and what he had offered to give in exchange for the cocaine was an unloaded firearm, which he showed to the drug-seller. The Court held, I regret to say, that the defendant was subject to the increased penalty, because he had "used a firearm during and in relation to a drug trafficking crime." The case was not even close (6–3). I dissented. Now I cannot say whether my colleagues in the majority voted the way they did because they are strict-construction textualists, or because they are not textualists at all. But a proper textualist, which is to say my kind of textualist, would surely have voted with me. The phrase "uses a gun" fairly connoted use of a gun for what guns are normally used for, that is, as a weapon.
When you ask someone "Do you use a cane?" you are not inquiring whether he has hung his grandfather's antique cane as a decoration in the hallway.
The Living Constitution or Living Tree theory holds that a Constitution must adapt to changing circumstances, and that is is proper, indeed essential, for judges to make such adaptations when they are needed, without waiting for formal amendments. This doctrine has been associated with both legal realism and judicial activism. In the US it was particularly associated with the Warren Court (under chief justice Earl Warren) Justice Thurgood Marshall wrote approvingly of it.
In Canada, which does not have a single written constitutional document, the "living tree" theory is more generally accepted. The Supreme court of Canada wrote in the Same-Sex Marriage case, December 2004:
The "frozen concepts" reasoning runs contrary to one of the most fundamental principles of Canadian constitutional interpretation: that our Constitution is a living tree which, by way of progressive interpretation, accommodates and addresses the realities of modern life.
A textualist would find such an approach totally unacceptable.