Now House Democrats are acceding to McCarthy’s requests. If the resolution passes, which it’s expected to do, future impeachment hearings will be more public, with clarified roles for Republican participation in the process (including some subpoena power) and protections for the president. McCarthy and other House Republicans will have to find a new line of defense.

The reason House Republicans lambasted their own rules in the first place was that arguing about process was politically more expedient than arguing about substance. The Trump administration used the same tactic when discrediting the Mueller investigation: It’s a witch hunt; it was started under false pretenses; it’s part of a deep-state conspiracy; it’s a bunch of angry Democrats. Never mind the possible obstruction of justice by the president of the United States, they implored—the important thing is that no one ever should have found out about it in the first place!

(After Mueller declined to accuse the president of any crime directly, Trump and his defenders added a substantive argument—“No collusion, total exoneration”—to the procedural argument.)

New scandal, same tactic. The Democrats announce an amorphous impeachment inquiry, and the Republicans attack it on process grounds. The whole point is to distract from the substance of the issue by, ironically, appealing to an innate sense of fairness and propriety.