And thus goes down the only substantive legal threat against Donald Trump -- for now. Judge Aileen Cannon has dismissed the entire indictment against Trump in the classified documents and obstruction case in Florida, ruling that Smith's appointment as special counsel was unconstitutional. 

In an 93-page ruling, Cannon scolded the Department of Justice and the executive branch for bypassing Congress with the appointment of a non-confirmed prosecutor:

Judge Aileen Cannon has dismissed the classified documents case against Donald Trump.

In a ruling Monday, Cannon said the appointment of special counsel Jack Smith violated the Constitution.

“In the end, it seems the Executive’s growing comfort in appointing ‘regulatory’ special counsels in the more recent era has followed an ad hoc pattern with little judicial scrutiny,” Cannon wrote.

That's a reference to the appointment of Robert Mueller in the Russiagate investigation, which Mueller later found to be unsubstantiated. Targets of Mueller's prosecutions on unrelated matters had challenged his standing on the same basis, but got overruled at both the trial court and at the appellate court. It never did get to the Supreme Court in those instances.

However, Justice Clarence Thomas made a pointed reference to the same issue in his concurrence in the Trump v US immunity case:

In this case, the Attorney General purported to appoint a private citizen as Special Counsel to prosecute a former President on behalf of the United States. But, I am not sure that any office for the Special Counsel has been “established by Law,” as the Constitution requires. Art. II, §2, cl. 2. By requiring that Congress create federal offices “by Law,” the Constitution imposes an important check against the President—he cannot create offices at his pleasure. If there is no law establishing the office that the Special Counsel occupies, then he cannot proceed with this prosecution. A private citizen cannot criminally prosecute anyone, let alone a former President.

No former President has faced criminal prosecution for his acts while in office in the more than 200 years since the founding of our country. And, that is so despite numerous past Presidents taking actions that many would argue constitute crimes. If this unprecedented prosecution is to proceed, it must be conducted by someone duly authorized to do so by the American people. The lower courts should thus answer these essential questions concerning the Special Counsel’s appointment before proceeding.

At the time, I predicted that Cannon would see this as a signal to take the constitutional question seriously. And take it seriously, she did:

In the end, there does appear to be a “tradition” of appointing special-attorney-like figures in moments of political scandal throughout the country’s history. But very few, if any, of these figures actually resemble the position of Special Counsel Smith. Mr. Smith is a private citizen exercising the full power of a United States Attorney, and with very little oversight or supervision. When scrutinized, this spotty historical backdrop does not “amply confirm[] the Attorney General’s authority to appoint the Special Counsel here” [ECF No. 374 p. 16]. Whatever marginal support the history may lend to Special Counsel Smith’s position, the inconsistent patchwork of practices detailed above does not show that Congress ratified—or acquiesced to—the Executive’s use of Section 515 (or its predecessor statutes) to appoint special counsels like Mr. Smith. And it is far from sufficient to overcome the plain language of Section 515, which, as covered above, does not confer upon the Attorney General officer-appointing power but merely establishes procedures (oath and commission) for already retained special attorneys who act in an assistant capacity. Special Counsel Smith is not an assistant.

 Cannon was not impressed with Smith's insistence that Attorneys General can create officers at will. Noting that US Attorneys are officers created and confirmed by Congress, Cannon refused any reading of the statute that then allows AGs to simply create identical officers outside of Congress' explicit authorization:

Special Counsel Smith argues that Section 533(1) confers on the Attorney General the authority to appoint special counsels, specifically, constitutional officers wielding the “full power and independent authority . . . of any United States Attorney.” 28 C.F.R. § 600.6. After careful review, the Court is convinced that it does not. Congress “does not . . . hide elephants in mouseholes.” Whitman v. Am. Trucking Associations, 531 U.S. 457, 468 (2001). Special Counsel Smith’s interpretation would shoehorn appointment authority for United States Attorney equivalents into a statute that permits the hiring of FBI law enforcement personnel. Such a reading is unsupported by Section 533’s plain language and statutory context; inconsistent with Congress’s usual legislative practice; and threatens to undermine the “basic separation-of-powers principles” that “give life and content” to the Appointments Clause. Morrison, 487 U.S. at 715 (Scalia, J., dissenting).

Finally, Cannon addresses the argument about whether Smith is essentially being hired as an "inferior officer" and thus below the threshold of Congressional authorization. Cannon weighs this carefully, but rules that Smith's unchecked power is at least as great as that of US Attorneys and therefore cannot be considered "inferior":

The Special Counsel Regulations give to the special counsel an exceedingly broad charge—to “exercise, within the scope of his or her jurisdiction, the full power and independent authority to exercise all investigative and prosecutorial functions of any United States attorney,” 28 C.F.R. § 600.6—and then impose virtually no mechanism for supervision or control by the Attorney General. Several key features inform this view, tracking the regulations on the subjects of consultation, supervision, and countermanding (with removal to follow later)[.]

Had Merrick Garland appointed a US Attorney to this position, this question wouldn't have come up at all. As a private citizen, however, Smith has been created a prosecutor with massively broad authority without even consultation with Congress. As Cannon rules here and Thomas argued in Trump v US, that has enormous implications for the balance of power and oversight on the executive branch's prosecutorial power in particular.

Cannon ordered the case dismissed, to cancel all further hearings, and to have the clerk close this case. Cannon did limit this order to this case, however; Smith's case against Trump in the DC circuit with Judge Tanya Chutkan remains active and unaffected by this ruling. Chutkan has already dismissed a similar motion challenging Smith's standing in that case.

Smith will almost certainly appeal this ruling to the 11th Circuit, which has intervened a couple of times before to reverse Cannon rulings. Cannon wrote a very compelling argument against Smith's standing, though, so it may not be as easy to overrule in this instance. If they do, this will go quickly to the Supreme Court, where any ruling will impact both venues.

In the meantime, the case in Florida is dead in the water. And one has to wonder whether Chutkan might pause her case if and when Smith appeals this ruling. It is very unlikely, in other words, that Trump will face any more criminal trials before the election. 

Update: Don't forget too that the immunity ruling has already complicated the January 6 case over which Chutkan is presiding. The Supreme Court ordered her to conduct a separate hearing on the immunity issues, and any rulings that proceed from it can be immediately appealed.