It’s tempting to think — and hope — that attacking inequality doesn’t mean we have to hurt those at the top. This idea has become a central response from conservatives to the current debate inspired by Thomas Piketty’s book and proposal for a wealth tax.

“The question is how do we help people at the bottom, rather than thwart people at the top,” Greg Mankiw, the Harvard economics professor, recently asked. Veronique de Rugy of the Mercatus Center at George Mason University asked: “Why not try to increase access to capital for more people, especially for those in the bottom, rather than try to hammer the ones at the top?” And Martin Feldstein, perhaps the dean of conservative economists, argued that to reduce persistent poverty “we need stronger economic growth” rather than “the confiscatory taxes on income and wealth that Mr. Piketty recommends.”

This argument isn’t a purely conservative one, either. Many liberals and moderates would no doubt prefer a kinder and gentler way to help the poor. But it doesn’t exist.

The rising tide of inequality does more than create great economic distance between income classes. It also produces higher barriers to mobility. Increased investment in the poor’s economic opportunities and in their children, their health care, their housing and their education will be needed to overcome those barriers.