One of the most striking aspects of American politics over the past decade has been the unwillingness of moderate/vulnerable Democratic Party members of congress to embrace the median voter’s view of this issue. In principle, it ought to be a potent wedge that sharply divides the Republican base from moderates and independents. But instead of moderate Republican politicians feeling political pressure to break with their leadership on taxes, we’ve consistently seen moderate Democratic Party politicians breaking from their leadership.
You do see issues where the public lines up strongly on one side but elites take the other side. (Free trade, immigration, raising the debt ceiling, for instance.) But usually these are issues where the public supports a position rejected by the bulk of policy experts. The interesting thing about tax cuts for the rich is that proposals to raise taxes on the rich aren't some fringe, populist fad. They command support from economists at places like Brookings and the Tax Policy Center. Conservatives have invested huge resources in legitimizing and promoting advocacy of lower taxes for the rich, and that view has attained a foothold in the debate, but it is nowhere near a consensus position.
So you have overwhelming public support for higher taxes on the rich, combined with strong expert support. And yet the only thing bipartisan about the issue is opposition to higher taxes on the rich. Why is that? Well, there's the asymmetry of passion you find on any policy with concentrated benefits and diffuse costs. Then you just have the overwhelmingly disproportionate political influence of high-income individuals, who comprise the most influential members of elected politics, media, and political giving. The combination of the two factors makes a position that by ordinary standards would be totally marginal a powerful force in political life.