I just saw this post (I think I responded to a different post of yours already). You have a tough dilemma, but I think there are pluses and minuses to each. Looking at everything you say, you seem to have a link to Boston which would be a minus if you move to DC. However, you want to have a career in politics which is--hands down--Georgetown, and overall Georgetown is simply the stronger university (and is one of the strongest universities in the world). I know people who have graduated from Georgetown and BC, and while both are strong--I still think Georgetown may be the wiser choice (certainly on a career growth level). On a more personal level, that's a bit tougher--cuz you can argue that having lived in Boston could be easier for you BUT you also can argue that there are very much benefits to living outside of your "safety" zone (especially if you ever want to be a political leader used to different settings and if you just want to know more about "life" in general). Lastly--keep this entire thing in perspective. This is a "3 year investment" in your career--if 3 years in Georgetown can mean much greater opportunities and progress in the long run for your life-long dreams, go for it! Your family and gf aren't going anywhere (really).
That being said, whatever you decide, you can not go wrong. Really, congratulations and good luck on your decision.