Unless Republicans repudiate Reaganite supply side (i.e., trickle down) economics -- which stands at the very heart of contemporary, Tea Party conservatism and is the only thing unifying the increasingly disparate social conservative, libertarian, and Chamber of Commerce wings -- they own this debacle.
It is clear that the increase in capital gains plays a large role in driving inequality trends, and, if we taxed such gains as regular income, that would help to reduce inequality. So, can one argue on the one hand that tax policy is inherently limited as a tool against rising inequality, and on the other, that we should employ tax policy to push back on inequality? I could invoke Walt Whitman -- "Do I contradict myself? Very well, then I contradict myself, I am large, I contain multitudes" -- and leave it at that. But better yet, let me explain. In reality, the evidence shows that increased inequality is a pretax story.