These breaks come in addition to the roughly $4 trillion package of tax cuts that President Trump signed into law in July. The legislation, passed entirely by Republicans, heavily benefits businesses and the ultrawealthy. It is projected to add trillions of dollars to the federal deficit and came with steep cuts to health care for the elderly and food stamps for the poorest Americans.
With its various tax relief provisions, the administration is now effectively adding hundreds of billions of dollars in new breaks for big businesses and investors. The Treasury is empowered to write rules to help the I.R.S. carry out tax laws passed by Congress. But the aggressive actions of the Trump administration raise questions about whether it is exceeding its legal authority.
Mr. Trump and congressional Republicans have attacked federal workers as instruments of the “deep state,” exercising power beyond anything authorized by the law. Now the administration is doing the same thing, several tax experts said, undermining laws that hit the ultrawealthy and big companies.
“Treasury has clearly been enacting unlegislated tax cuts,” said Kyle Pomerleau, a tax economist at the American Enterprise Institute, a right-leaning think tank. “Congress determines tax law. Treasury undermines this constitutional principle when it asserts more authority over the structure of the tax code than Congress provides it.”