There was a time when the left believed that a rising tide lifts ALL boats. Since then, they have lost their understanding of "ALL".
http://www.realclearpolicy.com/articles/2017/12/08/the_gop_tax_plan_is_pro-growth.html
http://www.realclearpolicy.com/articles/2017/12/08/the_gop_tax_plan_is_pro-growth.html