Do taxes narrow the wealth gap?

They can't constitute a full solution, argues Alan Viard:

Raising millionaires’ taxes may seem fair -- they can obviously afford to pay more. But, this policy has significant economic costs. Higher tax rates will encourage millionaires to report less taxable income, limiting the revenue inflow. And, the higher rates will discourage saving by the group that finances much of the business investment on which economic growth and wages depend. If we’re willing to accept those costs, tax increases on millionaires can be part of the fiscal solution. But economists and commentators across the political spectrum agree that taxing the rich cannot be the full solution -- basic math shows that closing the fiscal gap will also require entitlement cuts and tax increases on the broad middle class.

Larry Bartels counters. Apologies for the article being a little older than would normally be expected, but an article (even one from ten days ago) on the wealth gap begs to be accompanied by Friedman's comments on the issue. Originally, I had a video of Thatcher talking about a similar issue, but I thought this to be closer to the point.