Documents show Congress has received a President's tax information from the IRS in the past - CNN Politics

House Ways and Means Committee Democrats are arguing that newly reviewed documents dating to the Nixon administration reveal that the law a congressional committee used to request President Donald Trump's tax returns has been used to request presidential tax information from the IRS before and that committee received it.
https://www.cnn.com/2019/07/25/politics/trump-tax-returns-nixon/index.html