I too have a D interested in PoliSci/IR/Econ, but she is already a junior. 3 AP’s, 2 Honors, 1 regular Physics. Very glad she decided to switch from Calc BC to AB in the beginning of the year. Yes, she probably could have handled BC instead of AB and AP Physics instead of regular physics (no AP alternatives for Honors classes at our school), but that would also mean she’d be studying ALL the time and wouldn’t have time for all the extra-curricular she is doing and enjoying, including a community college class via DE. I support it mainly because it gives her a more balanced high school experience, less stressful and sleepless then many of her friends.
But looking at it from college planning perspective, it is the extra -curriculars and the essays that set kids apart and would make Princeton want your daughter over someone with same or more AP’s. I believe there is a certain threshold that needs to be met for a college to feel “yeah, this kid can handle our rigorous curriculum”, and anything above that won’t necessarily impress them. Adcoms won’t say to themselves, “wow, this kid took 6 APs instead of 4 most others in that school are taking.” Instead, they’ll be asking, “how did that kid contribute to their school and community while maintaining their academic standing, and what can s/he bring to campus?”
Since there is only so much any kid can handle and fit in their schedules, there will always be a trade-off. That being said, Con Law sounds great, your D will probably enjoy it a lot. My D will take it next year, although at our school AP CompGov is semester-long, and the other semester is IR. I too vote for Physics H instead of AP Bio. Best of luck!