Whether it can be undone in the future is besides the point. Trump rode in on a drain the swamp ticket and he's thrown a few dollars a month savings to the poor people. But it's calculated that he'll save up 11-15m dollars a year and Kushner 5-12m dollars a year with the new bill.

All of this is paid for by increasing the US deficit so there's a long term impact regardless of what happens in future elections.

One senator even said that his big business donors told him not to contact them again if the bill didn't go through. Who's being represented? Drain the swamp indeed...