The facts: 70% of gross domestic product (GDP) comes from consumer spending. Around 80% of U.S. households make under $100,000 per year. This is the middle (and "working") class. All the credible analyses of Romney’s tax plan indicate that it will take purchasing power away from the middle class and below (see link).
If you take purchasing power away from the middle class, you drag down the largest part of the economy…END OF STORY!
Please don’t call yourself a capitalist if you don’t believe in GDP growth.
On the Distributional Effects of Base-Broadening Income Tax Reform (Brookings)