there are no permanent friends or foes, only permanent interest

"Therefore I say that it is a narrow policy to suppose that this country or that is to be marked out as the eternal ally or the perpetual enemy of England. We have no eternal allies, and we have no perpetual enemies. Our interests are eternal and perpetual, and those interests it is our duty to follow."

there are no permanent friends or allies, only permanent interests,

there are no permanent friends or foes, only permanent interest

There are no permanent friends or enemies, but permanent interests in international relations.

reference:

http://michaelhurst999.wordpress.com/2011/04/26/permanent-interests-in-us-foreign-policy/

http://en.wikipedia.org/wiki/Henry_John_Temple,_3rd_Viscount_Palmerston

http://answers.yahoo.com/question/index?qid=20101013125330AAK2mco