Pretty obvious...

It’s not too hard to understand why everyone seeking the Republican presidential nomination is proposing huge tax cuts for the rich. Just follow the money: Candidates in the G.O.P. primary draw the bulk of their financial support from a few dozen extremely wealthy families. Furthermore, decades of indoctrination have made an essentially religious faith in the virtues of high-end tax cuts — a faith impervious to evidence — a central part of Republican identity. 
Recently, the Koch brothers said that unless their taxes are lowered, they'd have to lay off about a dozen Congressmen(R). Sad, but maybe true.