The escalating clash between District Attorney Alvin Bragg and Congressional Republicans over the role of Congress in a local prosecution — one of a former commander-in-chief, no less — implicates, and could imperil, two fundamental pieces of American bedrock — federalism and separated powers. Mr. Bragg’s prosecution strikes us as misguided and partisan. It is nevertheless his to make, unimpeded. 

That is being argued by Mr. Bragg’s general counsel, Leslie Dubeck. We do not endorse the alchemy by which Mr. Bragg is seeking to transmute a misdemeanor into a felony in the case against Mr. Trump. Nor do we have any enthusiasm for the facts of this case against a former president, particularly a charge that is more sordid than significant. We are, however, watchers of the wall that separates One Hogan Place from Capitol Hill.

That barrier’s primary brick is the Tenth Amendment, which ordains that ​the “powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.” This means that Congress’s powers are enumerated, the states’ are unenumerated. The Supreme Court has held that the “clearest example of traditional state authority is the punishment of local criminal activity.”

This is true even when there is a colorable claim that a state is prosecuting unjustly, and the defendant appeals to the feds for help. Younger v. Harris, from 1971, tells those defendants that the doors of the federal courthouse are blocked until the state has adjudicated their cases. Only then can they turn to federal courts. The Younger court planted itself among those — the Founders included — who signal loyalty “to the ideals and dreams of ‘Our Federalism.’”

“Our Federalism,” in the words of Justice Hugo Black, is the knowledge that the “entire country is made up of a Union of separate state governments” and that the “National Government will fare best if the States and their institutions are left free to perform their separate functions in their separate ways.” Born in the “early struggling day” of America, “Our Federalism” “occupies a highly important place in our Nation’s history and its future.”  

Justice Black was at pains to explain that “Our Federalism” does not “mean blind deference to ‘States’ Rights’ any more than it means centralization of control over every important issue in our National Government and its courts.” It is a government by way of Goldilocks, with “sensitivity to the legitimate interests of both State and National Governments.” The latter strives not to “unduly interfere with the legitimate activities of the States.”

Congress is not a court, and is prohibited by the Constitution from being one. The lawmakers after Mr. Bragg are themselves emphasizing that they do not intend to block Mr. Bragg’s work, only to monitor it. They are requesting documents, not exercising a veto. The pressure on the district attorney, though, appears to blur both the line between the federal and state sovereigns as well as the separation of power between the legislative and judiciary branches. 

This is a point we have marked in relation to the January 6 committee, which arrogated to itself powers that verged on the prosecutorial and flirted with the prohibition of attainder, in effect staging a trial of Mr. Trump before he was ever charged. That violated due process. In the case of Mr. Trump’s carrying on with Stormy Daniels, the discretion on whether to prosecute is Mr. Bragg’s. The rest is up to the jurors — and then the voters.