When Boechler v. Commissioner was argued, I wrote about how the statute in the case presented several grammar and usage quandaries. Now, the Supreme Court has unanimously agreed: The statute's text is a mess.

The Court didn't use the word "mess," but you could tell. Its opinion applied "traditional tools of statutory construction" to decide whether the statute "clearly stated" that a 30-day deadline for seeking Tax Court review was jurisdictional. But it failed to find the requisite clarity.

This is what the statute says:

[A] person may, within 30 days of a determination under this section, petition the Tax Court for review of such determination (and the Tax Court shall have jurisdiction with respect to such matter).

Because Boechler (a law firm) had petitioned on the 31st day, the government argued that the Tax Court lacked jurisdiction.

The Court quickly identified the central interpretive problem: The phrase "such matter" in the statute's jurisdictional clause "lacks a clear antecedent." Even applying the "last antecedent rule"—the idea that a word like "such" usually refers back to the nearest noun or noun phrase—didn't help. The government's argument that the statute withdrew Tax Court jurisdiction over late-filed petitions was "not clearly right."

But why did the government have to be clearly right? The Court explained. "Jurisdictional requirements cannot be waived or forfeited, must be raised by courts sua sponte, and . . . do not allow for equitable exceptions." If the court lacks jurisdiction, the case is over. Because "the jurisdictional label" is so consequential, the Court has sought to "discipline" its use by forcing Congress to "clearly state" jurisdictional requirements.

So when jurisdiction is at stake, having a "better" reading of the statute isn't enough. The statute must be clear. Clarity, the Court suggests, requires jurisdictional language that is expressly conditional.

The decision in Boechler offers at least two lessons for lawyers. First, skill with grammar and usage still matters. Boechler won because its lawyers used grammar and usage arguments to show that the statute was unclear. Second, courts treat jurisdiction differently. To win a jurisdictional claim, your grammar and usage arguments have to be more than a little better than the other side's—they have to prove clarity.

These lessons apply beyond Boechler's world of tax appeals. Federal and state statutes are filled with procedural timing requirements. Under Boechler's clear-statement rule, many of those requirements won't be jurisdictional.