PoliSci is top-5 major (in terms of popularity) that is typically in the Arts & Sciences school of a university. That means that 1) there is rarely a barrier to entry / it is rarely (if ever) over-subscribed, so no problem getting in and 2) it is pretty strong in most colleges.
How many credits you will actually be allowed to apply towards graduation varies by college, with state universities the most likely to give you the most credit and selective privates the least likely to give you very many credits. How many courses you will be allowed to apply towards skipping entry level classes is also college by college.
Here’s a more important question for you: why do you want to study polisci? Most of the usual pathways involve (expensive) graduate school. Because polisci programs tend to be pretty strong most places, unless your family will pay for all of both undergrad (no UG debt) and grad school, you double check your ‘dream’ schools against your budget. IMO at least 3 of the schools on your dream list are not worth full price for polisci even if you can afford it, and are definitely not worth any debt for polisci.