If she’s interested in International relations, she’s going to need grad school anyway (Tufts, G’Town, etc.) She’ll build her US network there.
Employment in the UK can be parlayed into a job in the US but would probably be required before she jumps right into the US job market.
I second the recommendation of adding a “critical language” - can make or break an application for foreign service.
She can apply to 1 of Oxbridge, St Andrews, 2 more (pick from King’s, Edinburgh, LSE, SOAS, Manchester) and a great “safety”, Queen’s Belfast with the “conflict” concentration (it requires 2 or 3 AP5s and 1350 SAT.)
Queen’s “Liberal Arts” with an International Studies concentration should also be a good option.
https://www.qub.ac.uk/courses/undergraduate/international-relations-conflict-studies-ba-l253/
https://www.qub.ac.uk/courses/undergraduate/liberal-arts-mlibarts-y300/
If she likes Bowdoin, look into Franklin&Marshall, which is relatively similar but easier to get into. Denison and, especially, Dickinson, offer good language &politics programs
Does one of your in-state options offer a “critical language flagship”?
(some examples
https://sllc.umd.edu/special-programs/arabic-persian/persian-flagship
https://www.brynmawr.edu/inside/academic-information/departments-programs/russian/russian-language-flagship
https://chinese.olemiss.edu/ )