Idealism: Idealists have some sort of universal political ideal, which they believe the use of force and/or international pressure is justified in achieving -- such as, for example, neolibertarians; who favor foreign interventionism to prevent natural rights from being violated abroad.
Realism: Realists believe that the international arena is a lawless free-for-all, and are interested in, and only in, what's in the best interests of their own sphere of influence.
Isolationism: Isolationists believe that they have no right to interfere in the affairs of other nations, except directly for self-defense. They aren't interested in spreading ideology, or expanding their influence abroad. This is distinct from realism in that realists are amenable to intervene abroad if it is in national interests neutralizing a potentially threatening power, or securing resources abroad for the home market).
You may choose any combination of the above, but it would be good if you explained why.
Personally, I'd consider myself a mixture of realist and idealist, somewhat more the former than the latter. My foreign policy philosophy so far is as follows: First and foremost, a nation is beholden to its own constituents, securing its own interests, resources, and geopolitical importance. This does not mean a nation must at all times act in a selfish manner. Displaying magnanimity towards the rest of the world, assuring global security; is a very good way to display the relative power and influence of a nation, and at the same time claim the moral high ground. I don't believe that a nation has the moral obligation to intervene to promote peace, security and stability abroad; but I do believe that doing so is beneficial to the nation from a spiritual standpoint, as it bolsters the morale and pride of its constituents.