Of course, no one remotely credible backs this up. Not the Tax Policy Center, not the Tax Foundation (which uses relatively rosy assumptions about growth), not the Penn-Wharton Budget Model, not Goldman Sachs, not the usual gang of Republican economists.
Not even the Joint Committee on Taxation, Congress’s nonpartisan internal scorekeepers on such matters, has found that the bill would be self-financing. Its most recently available analyses determined that even after accounting for economic effects, both the Senate and House bills would still cost about $1 trillion over the coming decade.
And that’s assuming many of the tax cuts actually expire after a few years, as the bills are currently written. If you take out the budget gimmicks and instead assume these tax cuts will be extended by future Congresses — as Trump officials and House Speaker Paul D. Ryan (R-Wis.) have promised — the price would be closer to $2 trillion, according to the Committee for a Responsible Federal Budget.
Faced with such dismal assessments of their party’s signature policy proposal, Trump officials have scrambled to find counterevidence.
In November, Treasury Secretary Steven Mnuchin claimed that the administration had already published a study proving that the bill paid for itself, though Treasury could not actually point to any such study. If anything, the department had removed research from its website that proved inconvenient for its claims about trickle-down economics.
But finally, on Monday, Treasury produced a report that purported to support the administration’s conclusions.
Well, “report” is a strong word. It was, in fact, a one-page news release containing no actual analysis or data, just fairy dust.
Rather than calculating the growth rate produced by the Senate tax plan, or any tax plan at all, the release merely . . . assumed a big growth rate. Then it said that if that growth rate happened to materialize, the plan would produce a whole lotta revenue. Enough to plug a big budget hole, even!