Congress gets to see Trump’s tax returns. It shouldn’t have taken so long.

Alas, the court’s decision does not assure that Mr. Trump’s tax records will ever become public or that future presidents — or presidential candidates — will not follow his lead in refusing to voluntarily disclose their own.

Restoring the norm under which presidential contenders voluntarily disclose their tax returns — followed by nearly every major-party nominee since Nixon — is important. Voters should expect to know what financial conflicts of interest they might bring to the job. And in Mr. Trump’s case, those records were especially relevant, given that he headed a sprawling and secretive privately held business. In addition to his tax records, he should have provided a detailed accounting of his holdings and interests. His refusal to do so became glaring as Mr. Trump pressed to reform the tax code in 2017. Americans could only guess how its provisions might personally enrich the president and his family.

If presidential candidates do not voluntarily share their returns, Congress might try to impose new rules. So could state lawmakers. In response to the Trump tax return saga, for example, New York legislators passed a law in 2019 allowing state officials to give congressional investigators the tax information they have on file. State lawmakers could also write laws that mandate the automatic release of candidates’ state tax returns after they claim major-party presidential nominations.

But it should not come to that. It would be healthier for the country to see candidates once again perform essential acts of honesty and transparency — not because they have to but because voters deserve it.