The fraud case brought by the Trump administration against New York’s attorney general, Letitia James, could be just what the doctor ordered to prop up the prosecutor. That at least is our takeaway from the raucous rally held this week for New York City’s would-be mayor, Zohran Mamdani. Ms. James ascended to the rostrum and delivered a barnburner that dilated at her persecution at the hands of the 47th president. Weak law, powerful politics.

If anyone ought to know how criminal charges can be converted into electoral rocket fuel, it’s Mr. Trump. The four felony cases against him — and Ms. James’s civil fraud trial — boosted, we reckon, his political fortunes in the 2024 Republican primary and in the general election. Efforts to disqualify him from the ballot as an insurrectionist led to the Supreme Court, by a nine to zero margin, ruling that states had no such prerogative to block him.

Whatever the particulars against Mr. Trump, his reelection over Vice President Harris amounted to a rebuke of what the 47th president calls “lawfare.” President Biden maintained that the prosecutions brought by Special Counsel Jack Smith were not political. Mr. Smith’s appointment days after Mr. Trump announced his run for a second term undercut that disavowal. As did his rush to try Mr. Trump before the 2024 election.

Which brings us back to Ms. James. At the rally she declared that “We see powerful voices trying to silence truth and punish dissent and, yes, weaponize justice for political gain. We are witnessing the fraying of our democracy, the erosion of our system of government … I stand on solid rock, and I will not bow, I will break, I will not bend, I will not capitulate, I will not give in, I will not give up.  You come for me,  you’ve got to come through all of us.”

One need not be a partisan of Ms. James to recognize the force in such rhetoric. It could be that the case being built by the government is a robust one, as the lead prosecutor, Lindsey Halligan, asserts. The four corners of the indictment, though, do not strike us as especially compelling. Mr. Trump’s public urging of the Department of Justice to convict Ms. James could provide fodder for a motion to dismiss.

Mr. Trump, on the 2024 campaign trail, declared that “My revenge will be success.” His second term, still young, has had no shortage of achievements. Not least of which is securing the Southern border or the return of Israel’s 20 hostages this week. It is hard to see how the case against Ms. James — or for that matter, against the former director of the FBI, James Comey — does anything except elevate their stature.

We have speculated that one salutary benefit of lawfare launched from every direction is that the baleful practice “could end not with a bang but a whimper.” That could yet come to pass. In the interim, though, Mr. Trump still has three years to govern and a midterm election to win. The revulsion of Americans at prosecution as politics by other means helped deliver Mr. Trump back the White House. So no one knows this boomerang better than he does.