To make America great again, making Microsoft, Google, and General Electric American again seems a good place to start.

Technically, those companies remain American. Their profits, on the other hand, claim a more diverse lineage. But Google is as Irish as Elizabeth Warren is Indian and Merck is as Bermudian as Rachel Dolezal is African American.

Bringing those offshore trillions back to the United States means making this country more hospitable to business. The administration’s proposed cut in the top corporate rate from 35 percent (more if one includes state taxes) to 15 percent serves as a first step.

A second, important step involves taxing U.S. corporations on profits sheltered overseas. U.S. corporations currently keep an estimated $2.5 trillion offshore. While loopholes and accounting tricks always shielded corporate profits from the taxman, the brazen manner by which foreign subsidiaries enable American companies to evade U.S. taxes makes a farce of the law.

Corporate income taxes constitute about nine percent of federal revenues. During the first 30 years of the federal income tax’s existence, revenues from corporate taxes usually eclipsed its revenues from individuals even when corporate rates did not exceed the top personal rate. As late as 1943, federal receipts from income taxes on corporations eclipsed those from individuals. Now, for every five dollars Uncle Sam pockets in individual income taxes, he takes a little over a dollar from corporations.

The corporate rates during World War II boosted to their highest levels in history for understandable reasons. But the current combined state-and-local rate that approaches 40 percent stands at a relatively high level historically speaking (and levying such a high rate when not trying to beat the Nazis ensures only that we beat ourselves). The top rate remained under 15 percent, a number familiar to anyone familiar with Donald Trump’s plan, prior to Franklin Roosevelt’s second term. Yet, in those years federal receipts for income on corporations almost always ran higher than those for individuals.

And compared to other nations, U.S. corporate taxes also appear quite high. According to the Tax Foundation, only Chad and the United Arab Emirates impose upon corporations a higher rate. Cuba, Venezuela, China, and other nations ridiculed by Americans for 20th-century statism atavistically surviving into the 21st century allow companies to keep more of what they make (though when the government owns so many of the companies the point is probably moot).

A 35 or 40 percent corporate rate effectively tells companies to take their business elsewhere. So, a dramatic reduction seals the invitation and rolls out the welcome mat. But old habits die hard, and the federal treasury likely leaves at least a trillion on the table even after profits return in the wake of the rate cuts.

What to do?

Tax U.S. corporations on the difference between the advantageous rate they pay sheltering money in foreign countries and the rate here. So, if a U.S. company prefers to pay Irish taxes, the federal government should impose a tax that recoups the difference between the ten percent rate the company pays overseas and the prevailing rate, be it 35, 20, or 15 percent, here. Already, the law calls for the IRS getting the difference between, say, what Microsoft pays Bermuda or Ireland or Singapore and what the U.S. levies upon companies once those profits return stateside. Rather than wait, seemingly forever in some cases, the IRS should impose the tax immediately.

Coupled with a more competitive domestic rate, a more aggressive imposition of that rate on scofflaws figures to repatriate much of the expatriated cash. In a few instances, companies may decide — unintended consequences matter — to not move the subsidiaries back home but to relocate the whole company abroad. But the IRS continues to tax them on U.S. earnings, so that decision does not pay off in practice as it does in theory.

The current setup isn’t pro-business but anti-American. And taxing at an exorbitant rate while reaping paltry revenues isn’t taxing the rich but fooling the rest.

Hunt Lawrence is a New York-based investor. Daniel Flynn is the author of five books.