Are there any effective research efforts into combating wealth inequality? There seems to be no "correct" answer in combating wealth inequality; however, we should attempt to use different methods to combat inequality in cities, then counties, then states, then countries. 

However, Politics is a huge barrier. Politicians are afraid to make any drastic efforts. 

I don't want to sound opinionated so I won't ask, "What are the best ways to combat wealth inequality". Instead, I will ask, "Are there any effective research efforts into combating wealth inequality"?

I also made a similar post on wealth distribution (for you to see) but the question was deleted for being too broad.
There is a lot of research into this area. You might want to look into the papers of Angus Deaton, Thomas Picketty, Gabriel Zucman, Emanuel Saez or Branko Milanovic for starters.

Especially, Emanuel Saez directly focuses on optimal taxation under different social preferences - including utilitarianism and ralwsianism where reducing inequality matters.

However, most research is on income inequality because wealth inequality is incredibly difficult to measure or track.

You might want to start with this paper and papers cited therein:


  Piketty, T., Saez, E., &amp; Zucman, G. (2013). Rethinking capital and wealth taxation. Arbeitspapier, Paris School of Economics, UC Berkeley und London School of Economics.


PS: Also this is tangent to your question but I would not be so hard on politicians - even assuming that they are completely enlightened social planners in many completely valid moral systems inequality does not matter. Reducing inequality does not necessary means reducing poverty if we measure it in absolute sense and not relative. 

This is also a main reason why there is no single agreement on the issue. Combating inequality is not just economic question but question for moral philosophers as well and right answer will vary depending on your personal values and morals