How can Congress subpoena someone taxes???
There is a 1924 law that stipulates the Treasury Department “shall” turn over “any return or return information” requested by the chairs of the tax committees........
For transparency, here is the tax law referred to:
Upon written request from the chairman of the Committee on Ways and Means of the House of Representatives, the chairman of the Committee on Finance of the Senate, or the chairman of the Joint Committee on Taxation, the Secretary shall furnish such committee with any return or return information specified in such request,
except that any return or return information which can be associated with, or otherwise identify, directly or indirectly, a particular taxpayer shall be furnished to such committee only when sitting in closed executive session unless such taxpayer otherwise consents in writing to such disclosure.
Notice the parts in bold. The secretary can furnish any information as long as it doesn't identify a particular taxpayer...which really doesn't make sense...but those are the words.
It also says this can only be done in closed executive session. Which means any information gained there are secret and confidential. Makes me wonder even if they did get the returns, would they be able to use then for anything since they wouldn't be able to disclose that information to anyone.