When Justice Ketanji Brown Jackson begins her service on the Supreme Court, court watchers will be anxious to see how she approaches the role of interpreting and applying legal provisions, particularly the Constitution. Jackson has had significant experience as a judge, but the role of a Supreme Court justice is different.

Justices are often guided by previous Supreme Court decisions, but ultimately they do not have to follow them. It is Americans’ hope, in fact, that if a prior decision (e.g., Plessy v. Ferguson’s “separate but equal” standard) has applied the Constitution wrongly, the court will correct that when the issue comes back (e.g., Brown v. Board of Education overturning the Plessy decision). Lower court judges, by contrast, are bound to follow Supreme Court precedent.

When Jackson writes or joins an opinion, the news coverage will likely focus on the outcome. But far more significant is how a justice approaches the interpretive process.

In a 2018 report, the Congressional Research Service identified eight “methods that have been employed when interpreting the Constitution.” These are “(1) textualism; (2) original meaning; (3) judicial precedent; (4) pragmatism; (5) moral reasoning; (6) national identity (or ‘ethos’); (7) structuralism; and (8) historical practices.”

The report describes each of these methods, but this post will simplify to suggest two general approaches the justices often take to applying and interpreting constitutional provisions. Understanding the approaches usually requires a more nuanced framework than a simplistic division of “conservative” and “liberal,” or whether a justice was appointed by a Republican or Democratic president.

As noted recently, one important approach is originalism. The basic idea is that the provisions of the Constitution are best understood in terms of how the language of the Constitution would have been understood at the time it was ratified. The rationale is that ratification marks the constitutionally decisive point at which a provision becomes part of the Constitution (under Article V). So, great effort should be made to determine as much as possible what the people of the United States, who ratified the law, understood they were approving.

Sometimes this approach is mischaracterized as an effort to apply the intention of the framers. That, however, is too limited, since the intent of a drafter of a provision could be drastically different from the understanding of the ratifiers. It would hardly be right to vest in the people of the United States authority to adopt constitutional law, while tying the meaning of that law to the private motives of delegates to the Constitutional Convention, or to legislators who proposed an amendment.

Thus, it is not, contrary to some popular perception, all about James Madison’s point of view. It is also not just an exercise in looking up terms in the dictionary.

Of course, this approach can create challenges when a constitutional provision is purposely somewhat vague (like “cruel and unusual punishment”).

Another influential approach, with no particular label, looks at the Constitution at a higher level of abstraction, seeking to understand the conceptual meaning of the text more than a fixed meaning. The advantage of this approach to proponents is that it allows justices to reach results consistent with current understandings of fairness.

An example might be a passage in a 1992 decision on Pennsylvania’s abortion law. The three justices who wrote the opinion were applying the term “liberty” in the 14th Amendment:

These matters, involving the most intimate and personal choices a person may make in a lifetime, choices central to personal dignity and autonomy, are central to the liberty protected by the Fourteenth Amendment. At the heart of liberty is the right to define one’s own concept of existence, of meaning, of the universe, and of the mystery of human life. Beliefs about these matters could not define the attributes of personhood were they formed under compulsion of the State.

It is hard to imagine that the ratifiers of the 1868 amendment would have had abortion in mind at all. But an expansive reading of a term they did use can allow justices to feel confident that they can resolve legal questions that might not have been contemplated at the time the Constitution was written or ratified.

The benefit of this approach is that it is obviously significantly more flexible. The drawback is that it can introduce a large degree of subjectivity into constitutional interpretation.

The significance of these approaches lies in a foundational reality that is so obvious that it is not often remarked on: We have a written constitution. That means, of course, that its words matter. The exact significance of these words, of course, depend on how justices understand them and apply them – in other words, their judicial philosophy.

Understanding the court requires understanding this reality rather than thinking only in terms of which party wins a case, or about the political party of the president who appointed an individual justice or a majority of the court. As Jackson takes her place on the court and begins to author opinions – whether in the majority or in dissent – it will be important to look beyond the political or media narrative to see her approach to interpreting the Constitution and consider what that means for the law.