Before the tax cut, the US Corp. rate was the highest OECD rate in the world. Also, the U.S. tax rate was 16 percentage points higher than the worldwide average of 22.8 percent and a little more than 9 percentage points higher than the worldwide GDP-weighted average of 29.8 percent.
Out of 173 nations worldwide, only Chad and the UAE had higher tax rates.
Compare the former US tax rate of 39% to Ireland's 12.5%.
Hmm, I wonder why US corps. like Burger King, Mylan, Johnson Controls, Liberty Global, etc. all did tax inversions?
How much corp. income tax revenue is the US getting from those corps. now?
In a competitive globalized economy where I call Microsoft support and get a person in India, lower corporate tax rates are important in keeping the US competitive.
https://taxfoundation.org/corporate-income-tax-rates-around-world-2015/