Why should any multinational base itself in the US under your proposal. Apple could shift HQ to Ireland or China or France or even Germany and net tens of billions a year more.

Apple doesn’t need to manufacture in the US. It doesn’t need to base most marketing/sales/finance in the US. It could leave just software and design in CA, and honestly report far lower US profits, and it wouldn’t owe the US another dime on foreign profits.

In fact, given 2/3s of their profits are international, they should do this now. Why pay the US an additional $10B a year in taxes on computers and phones made in China and shipped everywhere but the US?

Well, if you don't distinguish...then you're just taxing a company who has a foreign subsidiary and takes out a loan. Which seems sort of arbitrary, no? You wouldn't want to tax that across the board for the same reason that you don't tax loans generally.