Congress has no authority to demand a president’s tax returns.
It will be interesting to see what kind of “cover” they generate to try and get at his tax-returns. It will be even more interesting when he says NO and forces them to go to court, via lawsuit. Because discovery works both ways.
“Congress has no authority to demand a presidents tax returns.”
Now, the Finance Committee MAY have the authority to demand to see any particular taxpayer’s return...but given that Trump has been thoroughly audited for many years running, I cannot imagine the issue about which they are investigating - except the issue of a pure political stunt. If Trump gets this information subpoenaed, he should resist...and, perhaps, someone at IRS might investigate Maxine and why she has a multi-million dollar mansion on a Congressional salary.
Yes, they may have authority to investigate the President for crimes he may or may not have committed while in office, but they have no jurisdiction to investigate his past tax returns before he was elected.
Trump’s lawyers should just cite Watkins vs. United States and refuse:
“Watkins v. United States, 354 U.S. 178 (1957), is a decision of the Supreme Court of the United States that held that the power of the United States Congress is not unlimited in conducting investigations and that nothing in the US Constitution gives it the authority to expose individuals’ private affairs.”
https://en.wikipedia.org/wiki/Watkins_v._United_States