if you want to do social change work, enjoy a thriving career, and are focused on some type of graduate degree, there is no more useful/flexible option than an mba, jd or mpa

at one time i might also have recommended an msw or lcsw, but these days i really don't see it.

msw/lcsw will pigeonhole you into service work

something poly/sci, diaspora, or peace related as you've suggested here, into academia

the one other option is to consider is something in planning or economic/community development, but even that will direct you into that specific corner of the work

for broad options, i'm very confident that an mba, jd or mpa is where its at

probably not what you wanted to hear, but very much the truth

the other option is to forgo grad school altogether and grind it out from the bottom up, or involve yourself with a start-up flavored shop, but i used the word grind intentionally - it's not a path i'd suggest if you have other options.

one thing i might suggest, is to identify the type of organization you think does the most exciting or admirable types of work, then identify the top organizations of that type, and check out what backgrounds the folks on their leadership teams have. similarly, see if any of them host fellowships, and find out what types of grad work their current fellows are involved in