When the Supreme Court sits tomorrow to sort out Arizona’s immigration law the word to listen for is “uniform.” No doubt there will be talk, too, about the part of the Constitution known as the supremacy clause, which establishes the Constitution and the laws and treaties made under it as the “supreme law of the land” and requires that “the judges in every state shall be bound thereby, anything in the constitution or laws of any state to the contrary notwithstanding.” But the part of the Constitution that’s likely to come in for the most discussion is the grant to the Congress, in Article One Section Eight, of the power “establish an uniform Rule of Naturalization.”

One doesn’t have to read too far into the history of the founding era to grasp that the word “uniform” was the key to the thing. In 42 Federalist, James Madison began the discussion of the clause by noting: “The dissimilarity in the rules of naturalization has long been remarked as a fault in our system, and as laying a foundation for intricate and delicate questions.” He then goes into the jumble of descriptions by which, under the Articles of Confederation, rights were parceled out to the “free inhabitants” and “free citizens” and “the people” of each state or several states.

“There is a confusion of language here, which is remarkable,” he complained. He then goes on to sketch the illogic and injustice that could follow from having state-by-state arrangements. Then, concluding the part of the essay related to naturalization, he writes: “The new Constitution has accordingly, with great propriety, made provision against them, and all others proceeding from the defect of the Confederation on this head, by authorizing the general government to establish a uniform rule of naturalization throughout the United States.”

Now it doesn’t logically follow that no state can have anything to do with immigration. Arizona, after all, did not legislate a new method of naturalization but instead just legislated requirements to enforce the uniform federal rule. This is pointed out in an editorial in the issue of the Wall Street Journal we’d like to think the justices of the Supreme Court will read Wednesday on their way to work. One of the points the Journal makes is that the Democrats had an opportunity to improve the uniform rules of naturalization, back when they held not only the presidency but both houses of Congress. Instead, the used their political capital to ram through Obamacare.

In any event, the gods of newspaperdom have arranged it so that the Supreme Court is going to sit on this case as the New York Times is reporting on a study of the Pew Hispanic Center, which found that Mexican immigration into America — which the New York Times is calling the largest wave of migrants from a single country in American history — has stopped increasing after four decades and may be declining. Suddenly, the number of Mexican migrants in our country seems to be falling. The lack of jobs in the Obama economy may have something to do with this. The loss of these migrants augurs ill for the future. Already, there are reports that farmers in the South are finding it harder to get help with their harvests and are losing crops. At some point, our economy is going to start a serious expansion, jobs are going to be on offer, and America is going need all the help it can get.