Many schools on your list will have a DC Semester.
You have U of SC - my daughter attended their DC semester via College of Charleston who uses the U of SC program - but note you have to be in Honors to attend - so getting into U of SC alone isn’t enough.
The brownstone next to theirs was IU (Indiana).
If you want to be in DC or adjacent, it’s great but you don’t have to be. And internships weren’t hard to find - mine had 7 full time offers for her semester, 5 paid.
So as a basic question, are you using the Net Price Calculators at these colleges to confirm affordability? That is a good habit to get into.
Anyway, I always like to direct people with an IR interest to these Foreign Policy rankings of undergraduates. A lot of the names are the “usual suspect”, but some are interesting:
One college I thought might be worth flagging for you was the University of Denver. Again you would have to check their NPC, but they do have a robust merit program as well.
Anyway, they are on these lists thanks to their excellent Korbel School:
Note their International Studies program is already very interdisciplinary:
But Denver also has a secondary major program, which makes it easier to add a second major field. And Philosophy is one of the available secondary majors: