Thank you for all your advice. May I ask what you study/studied in graduate school?
I have an MSc in Econ, I'm in the second year of a PhD in Philosophy. I used to study at Warwick in the UK, I'm now enrolled at a doctoral programme in Germany.
Also, on the idea of studying abroad (yes, I'm American), have you found that admissions for good programs outside of the US are less competitive than those inside?
Not necessarily, but universities in Europe are very welcoming of international students, they're usually curious about their talents and perspectives. If you have a strong degree + some strong letters of recommendation from an American university, you're good to go.
I'm interested in studying abroad anyways. However, from what I've seen, it looks like international schools expect you to have a research proposal and know exactly what you want to study when you apply for a PhD program. In the US there's more of an attitude along these lines: "It's nice if you have an idea of what you'd like to study, but you'll probably change your mind to some degree. Hence we're not too worried about that. Just come, study, and meet some professors. You'll figure that part out later." And at this point, I don't know what I'd like to research; I have only a few ideas. But, then again, I have about a year and a half until I start applying
This is correct, European boards will ask for a relatively detailed research proposal - but you seem to have plenty of time to come up with something. You don't have to stick to your proposal though, you could, in theory, come up with a different project immediately after admission. This, of course, depends on whether you're part of a research team with a narrow focus; if so, it might be more difficult to do a 180 degree turn.
The point is: don't be too enamoured with the academic perspective, academia is full of flawed and insecure people with some diamonds in the rough. You can, however, establish a foothold in higher education if you so wish. Try to be as independent as possible, do what you love, and it'll work out.