Honestly, if Bernie Sanders could only do one single thing in his term - all that would matter in the end - is removing money from politics. Strict anti-corruption laws in your politics, especially enforcing a limit on political contributions to something like $5000 and not allowing non-direct contributions.
US is the most corrupt first world modern nation on this planet. Your main presidential candidate actually takes bribes outside her political donations via "speeches". Almost every politician you have takes donations from corporations which are treated as a higher priority constitute then your citizens due to the donation system.
Oh, and just because people confuse it. I'm talking about the actual definition of first world, i.e. first world - "West", second world - "East", third world - "Others". I don't think US is ahead of second world countries in terms of social policies and quality of life. The new first world is Scandinavia, Denmark, Switzerland, Canada, Australia, etc.