Sentence:  You may have misgivings about certain aspects of our military establishment - I certainly do - but you know any comparison of over-all American strength with over-all Soviet strength finds the United States not only superior , but so superior both in present weapons and in the development of new ones that our advantage promises to be a permanent <WSD>feature</WSD> of U. S. - Soviet relations for the foreseeable future . 
Meaning of the word marked with <WSD> tags:  a prominent attribute or aspect of something