I'd try something like Meguiar's "High Tech Swirl Remover" first. A very light polish, it "works" to an almost powdery state during application. Good stuff, safe for all of today's new paint systems (excepting those on German cars - they require even more special treatment due to their totally different paint systems).
Might try a "clay bar" as well. Or a paint prep solvent such as NAPA's Kleenz EZ.