Workers produce replicas of Kate Middleton's engagement ring at a jewelry company in Yiwu, China, April 27, 2011.  At the Portmeirion pottery works at Stoke-on-Trent, in Staffordshire, the kilns are fired up to get out the Kate and William commemorative cups and saucers. And so too at the Tangshan Hengrui Ceramics factory outside Beijing, where tens of thousands of "happy couple" plates are in production. At the TUI travel agency in Hanover, Germany the guided "Will and Kate Royal Wedding Tour" has done good business enticing tourists into London this balmy April. And at Franklin Mint in Philadelphia, the "Kate Middleton Royal Engagement Vinyl Doll" is proving a lucrative product line.  This is "Windsor Power" in action. Around the world, the April 29 wedding of Prince William to Catherine Middleton is delivering hundreds of millions of pounds in extra revenue for memorabilia manufacturers, and a major tourism boost for the British capital. Even in the cosmopolitan, 'Flat Earth' 21st century, interest in the future of the royal British bloodline remains a compelling phenomenon. (See how to knit your own royal wedding)  But what does the wedding have to say about modern Britain, and its relationship to monarchy? For better or worse, the United Kingdom still seems defined by its royalty. The Oscars this year were all about The King's Speech  the deftly woven story of George VI and his speech therapist, of royalty and disability, class and hierarchy. Before that it was The Queen, Stephen Frears's stark account of the clumsy House of Windsor confronting the death of Princess Diana. Across the world, millions still come to understand Britain through the medium of monarchy.  But at least they are coming to Britain: the literature, culture, history, commerce and politics of the U.K. receive a remarkable global airing thanks to the unquenchable human interest in monarchy. For families, of whatever creed or color, are naturally drawn to the stories of other families. Traditionally, in British history, this would be a brutal narrative of "hard power": princes locked in the tower; wives beheaded; sisters imprisoned. And great kingship was built on the effective display of martial valour. Think of William the Conqueror invading England in 1066; Richard the Lionheart and his Crusades across the Middle East; or King Henry V besting the French at Agincourt.  Today, it's all different. What modern monarchy represents is "soft power" in action  the ability of a state to influence the actions of another, or global opinion, through persuasion or attraction, rather than coercion. Part of the Windsor Family's function now is the selling of Britain abroad. Alongside the BBC, the Commonwealth, the English language, our diplomatic corps, and "Top Gear," modern monarchy is as much about trying to maximize the U.K.'s global leverage as any constitutional process: no longer a question of inviting Prime Ministers to take over Downing Street, but convincing FIFA to hold the World Cup in Britain; not European summits, but trade shows in Abu Dhabi. (See the top 10 royals who would have been terrible on Facebook)  After all, there is not much real power left. The Glorious Revolution of 1688 established the principle of Britain's "constitutional monarchy," whereby king and parliament ruled in uneasy harmony. The succeeding centuries saw the sovereign steadily lose the power battle, as Prime Ministers and Cabinet took the place of Kings and their Councils. By the mid-19th century, the constitutional analyst Walter Bagehot limited the royal prerogative to, "the right to be consulted, the right to encourage, the right to warn."  But if meaning at home ebbed away, it mushroomed abroad. The growth of the British Empire gave the British monarchy something to do. Queen Victoria became Empress of India in 1877, and her sons and grandsons were sent across the globe to govern provinces, open parliaments, and fight wars. In the process, the pomp and circumstance of British royalty scaled new heights. As historian David Cannadine puts it, "Between the late 1870s and 1914, there was a fundamental change in the public image of the British monarchy, as its ritual, hitherto inept, private and of limited appeal, became splendid, public and popular." The Delhi Durbar of 1911 saw King George V and Queen Mary bedecked in sapphires and rubies lording it over half a million Indian subjects with medieval-style flummery.  Today, in the 16 independent nations where the British Sovereign remains head of state, monarchy still matters. It is no accident that Prince William has recently headed to New Zealand in the wake of the Christchurch earthquake; and a royal tour of Canada is an early post-honeymoon priority.  For the success of the British royal family has always lain in its capacity for reinvention. After Empire, this took the form of a "welfare monarchy," with an emphasis less on the constitutional role and more on its practical purpose within civil society. The royal family's voluntarism and philanthropy, its role in sustaining the fabric of Britain's charities and clubs was what had to secure the Windsor dynasty.  Today, palace aides talk in terms of a "service monarchy": a monarchy for a "value-added age" where achievement and effort confer public legitimacy. So its role is, first of all, to promote British unity, pride and cohesion by virtue of the monarchy's "continuous history" and ability to rise above the short term fluctuations of party politics. Secondly, the publicity which surrounds the monarchy allows it to highlight excellence in private and public sectors as well as express condolence on behalf of the nation. Finally, in our individualistic age the nature of the monarchy's inherited privilege ironically allows it to emphasise the importance of public service and the voluntary sector. With his 350 charities, successful fund-raising powers, and benevolent business portfolio, William's father Prince Charles is regarded as having this royal role about right. Military service is another essential component of monarchy. It is has been a long time since a king led his troops into battle  George II at the battle of Dettingen in 1743, during the war of the Austrian Succession. Yet heirs, and most especially the spares, continue to serve. Not only do members of the armed forces swear allegiance to Her Majesty, but their very meaning is bound up with the monarchical ideal. The patriotism, implicit Protestantism and ethic of obedience the military embodies is regarded as a bulwark against the self-gratifying, materialist spirit of the age. (See an album of British royal weddings)  But in today's bifurcated world, such service is no longer so effortlessly commendable. When Prince Harry was discovered to have served with the Blues and Royals' in Afghanistan in 2007 (out to thump "Tommy Taleban"), the reaction was mixed: was the royal family participating in an act of colonial aggression or a high-minded moment of liberal interventionism? It was unclear whether his actions reflected the settled view of his realm. Suddenly, royalty and the nature of hard and soft power appeared more complex.  Deftly, Prince William has managed to steer a middle course. He understood the need to join the military and duly succeeded to officer training at the Military Academy Sandhurst. He passed out as a lieutenant and, since then, has followed in his father's footsteps by joining the Air Force. But he is also his mother's son and has begun to develop a sophisticated portfolio of charitable interests. He has worked closely with the Centrepoint charity for the homeless and, with Diana-like empathy, has joined rough sleepers on the street. Similarly, he has taken up her former position as President of the Royal Marsden hospital. His interest in Africa is pursued through the wildlife charity, Tusk Trust, while he supports access to sport through his presidency of the Football Association and English Schools' Swimming Association.  What many of these activities point to is the internationalism of modern monarchy. For all its mono-cultural, aristocratic limitations, the British royal family has a global sensibility. Since the expansion of Empire in the 1800s, the British monarchy has been a global force with subjects from New Zealand to Barbados, the Falkland Islands to Sri Lanka. In many parts of the world, particularly the autocratic Middle East and developing nations, the power of princeship remains a compelling asset. Yet it is also a strength at home. As British society, in the face of mass migration and the end of Empire, becomes ever more multi-cultural, the internationalism of the monarchy is an asset. Many post-colonial migrants and Commonwealth citizens embrace its pluralism. As political scientist John Gray puts it, "The monarchical constitution we have today  a mix of antique survivals and postmodern soap opera  may be absurd, but it enables a diverse society to rub along without too much friction."  Prince William needs to embrace that element of modern internationalism. He needs to begin to distinguish himself from some of the reactionary inclinations of the Windsor circle, and think about how royalty can work for Britain in the world  its businesses, arts, culture and interests. This means an end to the Little Englandism that sometimes envelops the Royal household and a richer appreciation of Britain's place in Europe. And why not some support for the things we do best not naturally associated with Buckingham Palace  modern architecture, urban culture, biological sciences?  However, it is a difficult balancing act. For, ultimately, the brand value of the royal family is about history and heritage, duty and tradition. In the words of the interwar diplomat Harold Nicolson, "a guarantee of stability, security, continuity  the preservation of traditional values." The meaning and history of Britain is far grander than the story of monarchy, but there is no point denying our Unique Selling Position within the global marketplace. "Our culture and heritage reputation is very strong around the world," according to Visit Britain spokesman Paul Eastham. "At the heart of that lies the monarchy." (See why anglophiles don't understand what makes Britain great)  All of which means the wedding has to be a bloody good show. Hatches, matches and dispatches  christenings, weddings, and funerals  are those signal moments when the Royal Family gets to define itself and, by implication, the nation. It does so this year, in times of economic austerity. As millions around the world expect a dreamland day, the Royal Family also has to be wary of conspicuous consumption. Britain needs to show some class: not the vulgarity of Dubai and Monte Carlo, but the quintessential elegance of an English wedding in Westminster Abbey. In the very setting where William's mother's funeral took place, the British royal family will once again show that it does pomp and circumstance, ritual and tradition like none other.  Of course, the wedding and all its costume trappings will lead some to regard Britain as a hidebound vestige of the past  and Prince William's ensuing actions have to counter that impression. Other nations might have better skills, bigger business parks, faster motorways; but we have history and culture and lots of it. So we might as well exploit it.  As our military overstretch in Afghanistan and Libya is painfully proving, British hard power is no longer what it was. And so our soft power assumes ever greater importance. Ultimately, monarchy is all about power: the retention and display of it. The challenge for Prince William and his generation is to understand what power we have left and what difference it can make. On the global stage, monarchy is an asset. With his wedding and in his marriage, Prince William must show he knows how to use it.  Tristram Hunt is a historian and, since 2010, a Labour Party Member of the British Parliament. He is the author of several books including The Frock-Coated Communist: The Revolutionary Life of Friedrich Engels.  See why Princess Diana mattered  See a TIME Special on the Royal Wedding
British royalty hasn't had much real power since 1688 but, with the decline of the empire, it has become one of the most effective projections of soft power in the world