international politics (as a field of study)
Refers to the academic discipline, not just current events. Often used in university course names.
He is majoring in international politics at university.
The international politics lecture is very interesting.
国際政治 refers to international politics as a phenomenon or practice, while 国際政治学 specifically denotes the academic study of it.
Compound of 国際 (international) + 政治 (politics) + 学 (study, -ology).