(Fifth in The interpretation of statutes and the denial of judges' power series.)
Textualism better than purposivism represents the American republican form of government, a system of checks and balances with the judiciary co-equal, because textualism supplies the courts with a basis for substantive opposition to the legislature. Textualism's natural fit with American constitutionalism was obscured after the demise of natural-law jurisprudence because the Supreme Court's resistance to progress was broken by an executive and legislative coalition, coercing the judiciary to speak the purposivist language of legislative supremacy. Not that the outcome was unfortunate: the point is that this deviation from constitutional blueprint was an unreliable basis for political planning. That the judiciary would eventually find a substitute for natural law was always likely, maybe inevitable.
If the courts are to check and balance the legislature, their opinions must have a source of legitimatization. The American constitution doesn't envision courts supplanting the legislature by the legislature's own devices, yet the constitution does envision that the judiciary exercise substantive checks and balances. When the Framers debated the constitution, they defended the independent judiciary because it could refuse to apply oppressive or unwise laws, a point Hamilton argued in the language of his time's natural-law jurisprudence. Today the only basis for the courts to disagree with the legislature outside the narrow set of constitutional cases is to oppose statutory text to legislative will. Textualism substitutes for conventional natural law the modern imperative to say what you mean.
Adherence to textualism doesn't let the courts veto any legislation that it thinks "oppressive or unwise," but laws that don't say what they mean are themselves a form of oppression. Such laws not only fail to inform citizens of their duties but allow the legislature to achieve indirectly what it would be ashamed to seek expressly. Misdescribing its intentions can also help the legislature engage in self-deception, so it may oppress by seemingly expressing the opposite.
When natural law broke down under F.D.R.'s direct political attack, the positivists' theoretical fire, and science's siege of theism's credibility, the will of the people was substituted for natural law, but it was a poor substitute. A unitary popular will, manifested in the decisions of elected representatives, can hardly check and balance itself. In retreat waving a purposivist white flag, the courts submitted to domination by other branches of government — at least when compared to the commandingly doctrinal laissez-faire economics that preceded. While the longevity of this arrangement proves the limited strength of interpretation's migratory tendency toward juridical coherence, it also illustrates that tendency. The eventual textualist reversal of direction occurred because the constitutional system allowed — was inherently conducive to — the courts' being much more than Congress's faithful servant. Textualism gave the courts room to assert independent power.
In principle textualism's initial form expanded judicial power beyond constitutional boundaries by providing few real constraints on interpretation, but increasingly textualism has become more restrained, almost merging with a restrained form of purposivism on its near left. This is its present internally driven trend, corresponding to a better fit with the constitutional blueprint and its purposes.
Next: The practical significance of the U.S. Constitution's democratic shortcomings.