If your ideology doesn't match reality, it's time to rethink your ideology

Via ThinkProgress:

Congressional Republicans and their party’s presidential nominee have both pushed plans to cut taxes on the wealthiest Americans in hopes that such a move would stimulate the economy and aid the recovery from the Great Recession. A new study, however, indicates that tax cuts for the wealthiest earners fail to generate economic growth at the same pace as tax cuts aimed at low- and middle-income earners.
...
What he found, though, is that the effect of tax cuts for the rich was “insignificant statistically,” as Reuters’ David Cay Johnston reported:

“Almost all of the stimulative effect of tax cuts,” Zidar found, “results from tax cuts for the bottom 90%. A one percent of GDP tax cut for the bottom 90% results in 2.7 percentage points of GDP growth over a two-year period. The corresponding estimate for the top 10% is 0.13 percentage points and is insignificant statistically.” 

Those of us who have paid attention to the economy over the past thirty years already knew that.  The Republicans probably know it too, but they're not in this for economic growth.  They're in it to help the rich.