I have been thinking a fair bit about improving institutional decision making practices. I buy the argument that if you fix systems you can make a better world and that making systems that can make good decisions is super important.
There are many things you might want to change to make systems work better. 
I am outside the US and really do not understand the US system and certainly do not know of any good analysis on this topic and any comments should be taken with that in mind, but my weak outside view is that campaign financing is the biggest issue with US politics.
As such this seems to me to be plausibly the most important thing for EA folk to be working on in the world today. I am happy to put my money where my mouth is and support (talk to, low level fund, etc) people to do an “EA-style analysis of US campaign finance reform”.