If Democrats in Congress succeed in their quest to get Donald Trump to cough up his tax returns, they’ll have another Republican president to thank: Warren G. Harding.

A century ago, the Teapot Dome corruption scandal engulfed Harding’s administration, spurring Congress to pass legislation that finally reclaimed its right to review private tax returns. It was a solid law, and remains so today: The legislative branch has the power to tax and spend, and the review of personal tax returns falls well within its rights and obligations.

The battle over the privacy of returns is as old as the income tax itself. The nation’s first such levy originated during the Civil War, and anyone could get the information. In fact, newspapers regularly published the amounts paid by the wealthy — a radical form of transparency that critics said went too far.

Congress prohibited the practice in 1870, and the income tax itself was rolled back not long afterward. In 1894, as part of a drive to reinstate the tax, Congress made the unauthorized disclosure of tax returns a misdemeanor, further strengthening privacy protections. But the Supreme Court soon ruled the tax unconstitutional, making the point moot.