Whatever today’s outcome in the Trump tax cases, originalists and textualists need a theory explaining why it’s OK to infer constitutional rules purely from structure (as opposed to the uncontroversial practice of using structure to illuminate the meaning of specific text).

Prof. John Manning (and others) have warned textualists about this sort of freestanding use of constitutional structure, which they would normally reject for statutory interpretation. But this use of structure apparently has a long historical pedigree.

Just one example. Here’s Chief Justice John Marshall, explaining that, notwithstanding the 10th Amendment, there may still be *implied* restrictions on state power based “on a fair construction of the whole instrument.”

It seems to me that Marshall in this passage is clearly endorsing freestanding structural inference, because his entire point is that the limits in mind are not expressly in the Constitution.

Abstract top-down reasoning from textualist first principles is thus probably the wrong way for originalists to approach structure’s role in constitutional interpretation. Such reasoning from high-level textualist assumptions seems to beg the whole interpretive question:

If originalists care about the Constitution’s text not simply because there’s something magical about writtenness, but because we remain bound by the original *law* that the text creates, we first need to know just how textualist the Founders really were.

As a result, to figure out the proper role of structure in constitutional interpretation, originalists should probably instead approach the issue from the ground up (so to speak), as a legal question of the Founding-era law of interpretation. Cc: @WilliamBaude @StephenESachs.

This requires historical research about Founding-era interpretive conventions. I don't know what the proper role of structure and freestanding structural inference would be under an originalist law-of-interpretation approach.

But I think we'd at least be asking the right questions, and a historical law-of-interpretation approach might offer a plausible way out of abstract textualist debates about first principles.