The main limit to executive privilege only can work with sitting presidents. The battle between Congress and the president, checks and balances, allows Congress to limit assertions of executive privilege through their powers over the president. It can refuse to confirm his nominees, ratify his treaties or pass his budget priorities. It can impeach him; one article of impeachment against Nixon concerned his refusal to produce evidence.

Trump’s assertion of executive privilege demonstrates the problem with allowing former presidents to exercise this authority. He has no reason to faithfully weigh, as an elected official would, the need of the public to understand the Jan. 6 attack against the need for confidentiality. Congress has no leverage.

Even if Trump has the authority to assert executive privilege, that’s not the end of the story. A president’s assertion of executive privilege isn’t absolute; it can be overcome by the need for the material, as demonstrated in the tapes case. Likewise, in the 1977 Nixon case, the court considered — and rejected — the privilege claim.

The real harm lies in delay.