  Events soon required a further elaboration of Burke's idea of the British empire. The continued use of coercion made the colonists more, not less recalcitrant. The practical need seemed to be for terms on which they would stay, in some sense or senses, under British rule. Their crucial claim was now that their right to tax themselves by their own legislatures rested on charters from the Crown, and that they were subordinate to the Crown alone, and not to Parliament. Burke gave still closer attention to the idea of sovereignty. It would be tactless to emphasize the sovereignty of Parliament, but it would be self-defeating to withdraw it explicitly and concede a sovereign right over taxation to the colonial legislatures. So now, in Burke's speech on Conciliation with America (1775), he focussed upon only one aspect of the complex idea of a parliamentary sovereign. The latter comprised in the British instance not only Lords and Commons, but also the king. Hence, by judicious emphasis, the item acquiesced in by the colonists could do some conceptual work: ‘my idea of an Empire…is…that an Empire is the aggregate of many States, under one common head; whether this head be a monarch or a presiding republick’; and it was emphasized that the rights of the colonists depended on this superior, for ‘the claim of a privilege seems rather, ex vi termini, to imply a superior power.’ As to a right to tax, Burke added on a later occasion, that though it ‘was inherent in the supreme power of society, taken as an aggregate, it did not follow that it must reside in any particular power in that society’, and therefore Parliament could delegate it to local legislatures. In short, ‘sovereignty was not in its nature an idea of abstract unity; but was capable of great complexity and infinite modifications.’ (SSC, W &amp; S 1981–2015, iii. 193).