Taken from the TG-119 which Bloomberg referenced:
In other words, companies would only be able to take a deduction on their U.S. taxes for foreign expenses when they also pay taxes on their foreign profits in the United States.
This makes sense. The proposal isn't forcing a company to pay extra taxes. It simply places tax incentives on layaway until the company pays its foreign taxes.
The question is: do foreign taxes count as expenses? They ought to.