Sentence:  Had the situation been reversed , had , for instance , England been the enemy in 1898 because of issues of <WSD>concern</WSD> chiefly to New England , there is little doubt that large numbers of Southerners would have happily put on their old Confederate uniforms to fight as allies of Britain . 
Meaning of the word marked with <WSD> tags:  something that interests you because it is important or affects you