The primary authors of the report — Ari Glogower, David Kamin, Rebecca Kysar, and Darien Shanske — describe the legislation as “a substantial blow to the basic integrity of the income tax” that will “advantage the well-advised in ways that are both deliberate and inadvertent.”

The authors cite a wide range of specific flaws, but their main argument is that the measure is gravely deficient at its core:

The most serious structural problems with the bill are unavoidable outcomes of Congress’s choice to preference certain taxpayers and activities while disfavoring others — and for no discernible policy rationale. These haphazard lines are fundamentally unfair and inefficient, and invite tax planning by sophisticated taxpayers to get within the preferred categories.

Glogower, Kamin, Kysar, and Shanske argue that some of the most egregious loopholes and schemes permitted by the legislation are that individual taxpayers

will be able to shield their labor income from tax by simply setting up a corporation and having their income accrue in the form of corporate profits. As a result, income that would have been taxed at the high individual rates is instead taxed at the low corporate rate.

Second, the legislation creates a huge incentive for anyone in a position to do so to change his or her status from employee to “independent contractor or a partner in a firm. The game is clear: Don’t be an employee, instead be an independent contractor or partner in a firm.” The ability to make this shift is available primarily to the well-paid.

The legislation, according to Glogower and his colleagues, also fails to present a coherent rationale:

the fundamental problem is the lack of any underlying logic in deciding who benefits from the pass-through deductions, and who does not. Independent contractors and partners benefit, but not employees. Why? An owner of real estate through a REIT benefits, but not the doctor in the building. Why? An architect benefits in some ways that a lawyer does not. And so on.

The bill encourages tax evasion. Glogower and his colleagues cite

opportunities to use rate differentials and ill-considered transitions to engage in transactions that serve to basically pump money out of the Treasury and into the pockets of well-advised taxpayers.

To provide an example, they use a company that purchased equipment under existing law, which provides them with tax breaks on the cost spread out over the years in a depreciation schedule. The new law allows companies to immediately write off the full cost of buying equipment, known as expensing.

“So,” the authors ask, “what does that mean?”

It means that old property can still get the benefit of expensing, but only if it is sold to another party. If the original owner holds it, they have to depreciate according to the old rules; if they sell it to another party, then suddenly the full cost is eligible for expensing, and the net effect is an immediate deduction of the existing tax basis of the asset. The parties can split the resulting surplus. It appears that the buyer of the asset could even lease it back to the existing owner, so that the property doesn’t even have to go anywhere.

I emailed some of the authors of this report for their individual thoughts.

Mitchell Kane, a law professor at N.Y.U., wrote in response that the bill will

create new incentives to shift tangible assets (and jobs) abroad. Given President Trump’s relentless message about U.S. jobs, it is incomprehensible to me that we are about to pass something that has this effect without any kind of meaningful discussion of the issue.

Daniel Hemel, a law professor at the University of Chicago, raised a crucial question about the long-term effects of the legislation’s adoption of chained CPI, a method of calculating the rate of inflation for the earned-income tax credit and other sections of the tax code that provide breaks to working- and middle-class families.