It's Treasury's job, no more and no less. That is one reason why so many Treasury Secretaries insist that they be the lead spokesperson for administration economic policy. It is not simply a power play. It is often the only way they can actively contain the many special interest pleaders in the modern Executive Branch. But standing up and then taking it on the chin in the current environment may not be enough.
More strategic planning is required.
Next week I'll suggest some ways that can be done. But the first and primary step is for Treasury to decide that it wants to be in charge of tax policy. Absent that step, no real strategic planning will occur, or, if it does, it will be merely pro forma and of little effect.