The Trump Administration has let it be known that they will be releasing a new and improved tax plan in the next several weeks. This will be a rewrite of the Trump campaign plan that was a rewrite of the original Trump campaign plan.

And we were told just last week by Treasury Secretary Steven Mnuchin appearing on CNBC that: “[W]e’re primarily focused on a middle-income tax cut and simplification for business. And … on the high end, if there are tax cuts, that they are offset with reduction of deductions and other things.” This echoes a line that Mnuchin used late last year when he said: “there will be no tax—absolute tax cut—for the upper class,” due to base broadening.

It won’t be a surprise if Trump followed up this claim with similar statements in his speech before a joint session of Congress this evening.

However, this claim is mathematically impossible. Put bluntly: The Trump tax plan will feature a large net tax cut for the top unless the Administration totally abandons a number of the significant tax cuts to which both the Trump Administration and Congress have committed themselves. No amount of base broadening—even far more aggressive base broadening than any leaders have proposed—can offset the tax cuts for the top which they have been pushing.

The Trump campaign plan—much like the House blueprint—features a massive regressive tax cut. The latest version of the Trump campaign plan had a tax cut equal to 13.5 percent of after-tax income for the top 1 percent, or an average break of over $200,000. In fact, half the tax cut goes to the top 1 percent. That reflects trillions in tax cuts through the individual income tax code as well as the corporate tax code. And, it also took into account a proposed cap on all itemized deductions set at $200,000 for a married couple.

But let’s say that plan is scrapped, and Secretary Mnuchin and colleagues are back at the drawing board. They start off with just three tax cuts at the high end to which both congressional Republicans and Trump have committed themselves: repealing taxes in health reform used to finance the expansion in coverage; repealing the estate tax; and lowering the top ordinary rate from 39.6 percent to 33 percent.

Let’s very generously assume for the moment that they have miraculously managed to arrive at a business tax reform plan that doesn’t cut taxes massively for those at the top—a goal to which plans outlined so far haven’t come close.

As showed in the below table, just those three provisions alone give a tax cut equal to about 6.5 percent of after-tax income for the top 1 percent, or over $100,000 on average.

But, then there’s the much-discussed, if rarely detailed base broadening. That can make things add up, right? The answer to that is “no.”

Even if every single itemized deduction were eliminated—no more deduction for state/local taxes, no more charitable deduction, no more home mortgage interest deduction—that would offset less than half that total tax cut. It can’t even pay for the cut in the ordinary income tax rate, let alone the rest. The table below details where the revenue would come from and how much.

And, I’d be willing to bet plenty that no policymaker is going to support complete elimination of itemized deductions! For instance, if just the charitable deduction were protected, the base broadening would offset only about one-third of the tax cut for those at the top from those three measures.

There simply aren’t other base broadeners that they’re willing to touch that could make up the difference. They won’t raise capital gains rates or reduce retirement saving accounts. The health exclusion—if they’re willing to touch it—is only a small benefit to the very top.

Perhaps they’ll assume runaway economic growth from these measures. However, as the Congressional Research Service has pointed out, effects are likely to be small, and any positive effect on labor from reducing tax rates may be largely offset by the negative effects of base broadening. Getting rid of the deduction for state and local taxes is just a marginal tax rate increase focused on people in high tax states, after all.

And none of this takes into account the large proposed tax cuts benefiting the highest income Americans via the business tax code, including rate cuts for corporations and a special low rate for “pass through income” (read income earned by lawyers and private equity and hedge fund managers). Republicans have been unable to come up with a way of paying for that as well.

In short, there will be a large net tax cut for the 1 percent in these plans unless Republicans are willing to lay off the large rate cuts and estate tax repeal. Treasury Secretary Mnuchin, President Trump, and congressional leadership should be challenged with that math.

Methodology

The numbers calculated above are rough estimates based on several different Urban-Brookings Tax Policy Center tables, as well as IRS Statistics of Income data.

Repeal of ACA taxes comes from TPC’s estimates for 2017 in Table T16-0283.

Repeal of the estate tax comes from TPC’s estimate of the estate tax as a share of pre-tax income 2017 in Table T16-0094. I convert this to share of after-tax income.

Reducing the ordinary income tax rate from 39.6 percent to 33 percent is derived from TPC’s estimate of the percent change in after-tax income for a one point reduction in the ordinary income tax rate in 2015 in Table T14-0110. I assume the percent change in after-tax income would remain the same in 2017 and would increase proportionately with the size of the rate cut.

All of the base broadening measures—except “other” itemized deductions—come from TPC’s estimate of these for 2016. I assume the percent change in after-tax income remains the same for 2017, and then adjust this down reflecting the fact that all of these deductions would be worth less with a top rate of 33 percent rather than 39.6 percent. Specifically, I multiply the TPC figures by 83 percent (the 33 percent rate divided by the 39.6 percent rate). The TPC estimates can be found in Tables T16-0162 (deduction for state/local taxes), T16-0163 (deduction for property taxes), T16-0164 (deduction for the mortgage interest deduction), and T16-0166 (deduction for charitable giving).