This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book explains that the theme of the national interest was one very close to Tory hearts, representing an idea of patriotism and the nation as best defended by Conservatives. The 'national interest' was a term much bandied about in August 2013 as politicians debated whether Britain should take part, as the Conservative-led coalition government proposed, in US-led action against the Assad regime in Syria. In contrast, today, political parties have provided the way to conduct mass politics in a society where democracy, a political and governmental system shaped by the right to vote, has been joined by democratisation with its demands for accountability. At the outset of Tory ministerial politics, Daniel Finch, 2nd Earl of Nottingham, a Secretary of State from 1689 to 1693 and in 1702-4, was particularly significant in that he encouraged the development of 'blue water' policies.