Way back in June 2016, House Republicans led by Speaker Paul Ryan and Ways and Means Committee Chair Kevin Brady unveiled a conceptually ambitious but somewhat vague tax reform proposal that featured the goal of lowering the statutory corporate income tax rate from 35 percent to 20 percent, paid for by closing unspecified loopholes and deductions. Last week, joined by counterparts from the Senate GOP caucus and the White House, Republicans rolled out a conceptually ambitious but somewhat vague tax reform proposal that featured the goal of lowering the statuary corporate income tax rate from 35 percent to 20 percent, paid for by closing unspecified loopholes and deductions.

Which is to say that in more than a year of work on the task of corporate income tax reform, Republicans have accomplished exactly nothing.

Operating in a purely partisan context where any legislation they pass would require the near-unanimous consent of congressional Republicans, they have not identified which loopholes they want to close. Nor have they so much as sketched out an illustrative example of what scale of loophole closing would allow for the 20 percent rate to be feasible. Nor, of course, have they identified any promising path forward for a bipartisan bill that would create more room to maneuver and increase the political viability of loophole closing.

But to actually pass a bill, Republicans will need, at some point, to actually commit some words to paper and spell something out. On taxes much more so than health care, without the detail work you’re not doing anything at all.

Republicans’ corporate tax math doesn’t work

The basic idea of closing loopholes and deductions to pay for a corporate rate cut makes a fair amount of sense. As Republicans like to say, America’s 35 percent statutory corporate tax rate is high by international standards and currently the highest in the OECD.

As liberals like to say, the effective tax rate that companies actually pay is considerably lower than that.

Taken together, these two facts strongly suggest that a lower — but less loophole-ridden — corporate tax rate could raise a comparable amount of revenue to the current system, but with less of a distorting effect on the overall economy. Because that hypothetical less loophole-ridden structure would be more efficient than the current system, one could probably get away with a tax rate that’s a bit lower than the 28 percent effective rate currently paid by American multinationals — if you closed all the loopholes.

Mitt Romney was quite aspirational in this regard, proposing a 25 percent corporate tax rate.

The Republican framework aims to be even more ambitious than that — cutting the statutory rate down to just 20 percent, making it lower than the effective rate currently paid and meaning there’s no way you could pay for it via simplification and loophole closing. Meanwhile, though the GOP tax framework does not name any loopholes to be closed, it does propose shifting the US corporate income tax to a purely territorial system — addressing the problem of companies sheltering their overseas profits from taxation by simply giving up on any effort to tax them at all.

One upshot of all this is that according to the Tax Policy Center, the elements of the GOP framework that are actually spelled out would increase the deficit by about $2.4 trillion over 10 years while raising taxes on individuals.

Given how unpopular the idea of a corporate tax cut is, this seems politically unworkable. But more directly to the point, it’s inconsistent with the budget the GOP is writing, which calls for “only” $1.5 trillion in increased deficits.

Republicans have unleashed a lobbying bonanza

One group excited about this hazy approach to policymaking is K Street lobbyists, who love nothing more than to whip clients into a panic about a possible policy change that they need to go collect billable hours to kill.

Page eight of the GOP tax framework states, ominously, that “numerous other special exclusions and deductions will be repealed or restricted” and that the framework will “modernize” various “special tax regimes” that “exist to govern the tax treatment of certain industries and sectors.”

The result, according to Kenneth Vogel of the New York Times, is “concerns among a wide range of businesses and industries about the prospect of losing valuable tax breaks — from preferential tax treatment for insurers to credits for renewable energy to a prized tax treatment used by the commercial real estate industry.” Concerns that “are being stoked by lobbyists, who are urging clients and prospective clients to get out in front of any changes that could eliminate or weaken sections of the tax code that benefit them.”

This is, of course, hardly a surprise. The tax code didn’t get the way it did by accident. Behind every special provision is a reasonably powerful lobby group, typically one that can offer at least a halfway persuasive account of why its particular priorities ought to be national priorities — arguments that are especially likely to seem persuasive to Republicans whose baseline instinct is to sympathize with the desire to not pay taxes.

But it’s precisely because the lobbying frenzy is so predictable that it’s remarkable the GOP has not actually done any work on the hard part of this. Instead, the result of five years’ worth of work between the Romney-Ryan campaign proposal and the Trump-Ryan governance proposal has been to shift from a hard-to-achieve 25 percent rate goal to an even-harder-to-achieve 20-percent rate goal. But to pass a tax bill, Republicans will at some point have to actually write a tax bill.

Punting is harder on taxes than on health care

Republicans faced a broadly similar problem of not having actually figured out any of the details of how they wanted anything to work on their Obamacare replacement bills. But by and large, members of Congress ended up addressing the gaps in their policy thinking by trying to punt decisions to other entities.

Most of the major iterations of Obamacare replacement faced the idea of congressionally imposed “caps” on Medicaid spending that would then be left up to states to implement. Rather than actually say in detail which kids would go without medicine or which grandmas would be kicked out of nursing homes, the goal was simply to set up a system in which someone or other would have to lose coverage and then punt the difficult issue to state legislators. Then to sell it to the public, Trump’s Cabinet just went on television to lie and say nobody would be losing Medicaid.

By the time replacement mutated into the Graham-Cassidy bill, Republicans were just block-granting everything — spending cuts were specified, but all the choices about everything were kicked to the states.

This doesn’t work on tax policy. The tax code is not an area in which it’s normal or even really feasible to grant discretionary authority to the executive branch, and it certainly can’t be granted to the states. Congress needs to say what it wants the corporate income tax rate to be, and if it wants that tax rate to be 20 percent and it wants to limit the amount by which the deficit increases, then it needs to spell out which loopholes get closed. Doing this in the context of a big, bipartisan deal would be challenging, but you’d have plenty of margin for error around specific provisions.

But doing it in the context of a hyperpartisan process where you’re trying to pass a giant tax cut for rich people that Democrats hate leaves you no room for mistakes. Any industry that wants to save any provision only needs to find three GOP senators — or two dozen House members — to kill it. This is presumably why Republican leaders keep not naming names as they go through different iterations of their plan. But unless they find some way to actually reach agreement on the crucial topic of which loopholes, exactly, are going away, there’s just no way for their tax plan to move ahead.