Sentence:  They recognized that slavery <WSD>was</WSD> a moral issue and not merely an economic interest , and that to recognize it explicitly in their Constitution would be in explosive contradiction to the concept of sovereignty they had set forth in the Declaration of 1776 that `` all men are created equal , that they are endowed by their Creator with certain unalienable rights , that among them are life , liberty and the pursuit of happiness '' . 
Meaning of the word marked with <WSD> tags:  be identical to; be someone or something