Tricky move. IRS tax is the measure of how $much the government can borrow from the banks. If there isn't any IRS tax, there is no way to get money to repay bank loans. The whole banking system might fail. No more loans to government - for Ukraine or Israel. At least there would be turmoil in the banking system. The US Treasury would have to take over the money system again. And there wouldn't even need to be any shutting down of the FED directly like JFK tried to do.