Treasury Secretary Steven Mnuchin has been citing a report that he says, once released, will show the GOP tax plan will pay for itself with economic growth. But that report doesn't exist, according to an economist in the Treasury office supposedly drafting models on the impact, the NYT reports.

Why it matters: Senators are aiming to pass their version of the tax bill today or tomorrow, and the question of whether economic growth can account for the tax cuts and avoid ballooning the deficit is at the heart of policy negotiations to win over holdouts on the bill. It's throwing some Republicans for a spin who are opposed to the mechanism that could be added to the bill to account for potential lack of economic growth.