Hi BrandyDances,
I don't know anyone who has successfully gone through this route (MPA/MA in IR after JD), but I am planning to do it myself! I'm happy to post my experience so that there is something out there for law students/law graduates/attorneys considering this path.
I graduated from a Top 30 law school in May, and passed the NY bar exam. I studied IR in college, took a year off after graduation for internships in the field, and entered law school with the intent to use my law degree to work in international affairs. The streamlining forces at law school made me question myself at every turn (wondering if I was crazy going after internships with non-profits and government rather than the coveted summer associate positions in law firms), but I managed to survive through the pressures by taking international law classes for electives and participating in as many international law oriented activities at my law school.
I really want to go back to school for several reasons. I think that the masters degree will be a great asset to my law degree in pursuing international legal work in the public sector, which I find is interdisciplinary in nature. Also, I miss being in an academic setting where I'm free to exchange my ideas on these issues with other students and professors.
I've talked to my friends who are in MPA/MA in IR programs (they are at HKS now, and were also accepted to other top programs when they applied) about their experiences with admissions, and I find them to be (refreshingly) different from law school admissions, or the law school experience for that matter (everything from journal experiences to OCI). My friends were surprised that I was asking questions about numbers, as in what GPA/GRE score combination would be competitive for MPA/MA in IR at X University. They stressed the importance of your SOP, your international experience, and your LORs over GPA and GRE scores. Obviously, it doesn't hurt to have strong numbers, but my impression from what I have learned thus far is that strong numbers alone do not guarantee admissions. This is a far cry from law school admissions (let's admit it, everyone slavishly follows the US News and World Rankings, and most applicants are accepted or rejected largely on the basis of their GPA and LSAT score) and the legal job search (with certain jobs at certain shops limited to students who have the GPA/class ranking desired by the employer, with very little room for exceptions).
Thanks to three years of law school finals and the bar exam, preparing for the GRE has been manageable thus far. I've got about a month before my testing date, and I feel pretty comfortable about being able meet my study goals before then. After all, we only get 2 months to prepare for the bar exam!
Anyways, I hope this has been somewhat helpful to you. I'd love to hear from other law students/law graduates/attorneys who have gone down this path. Any information would really help!