it is inherently unfair of our tax system to tax worldwide income of a US corporation.
If for example, Ford builds cars in Korea and sells them to China, why should the US get a cut of the profits if the income is not derived on US territory? No other country taxes profits earned outside its borders.
The tax code was changed to allow US taxation only on repatriated earnings (i.e. money brought back into the US.) This forces companies who make and sell products abroad to keep the profits offshore and the US economy is deprived of the investment.
There are trillions of dollars sitting in offshore accounts of Pfizer, Merck, Boeing, GM, Ford, Coca Cola, Pepsico, Microsoft, Intel, Cisco, Google etc. and if the law was changed, all that money wil be invested in the US, creating jobs here.
If forced, these companies could easily "invert" -- making the US company a subsidiary of an offshore entity and do this legally.