One of the Trump administration’s main justifications for disobeying a federal tax disclosure law is that Democrats’ request for President Donald Trump’s tax information is “unprecedented.”

Turns out that’s not quite right.

Democrats in the House of Representatives released historical documents Thursday showing that there actually is a precedent.

In the early 1970s, the Joint Committee on Taxation (JCT) used the same tax disclosure law to obtain tax information related to then-President Richard Nixon.

Amid a controversy over questionable deductions he’d used to lower his tax bill, in 1973 Nixon publicly asked the joint committee ― which is a nonpartisan panel of tax policy experts ― to pore over four years of his returns to verify that he’d paid what he owed.

The fact that Nixon invited Congress to look through his taxes while Trump has insisted on secrecy for his own is a big difference. But the new documents show that congressional investigators weren’t satisfied with what Nixon had volunteered.

The House Ways and Means Committee on Thursday revealed old letters between the JCT and the Internal Revenue Service showing that the JCT had asked for more information on Nixon, including returns for years prior to the ones Nixon volunteered.