Prince George has already earned the nickname "Republican slayer," so perhaps it comes as little surprise that the second child of the Duke and Duchess of Cambridge is already being touted — months before birth — for his or her potential as a political symbol.

Within hours of word spreading Monday that Prince William and Kate are expecting a brother or sister for 13-month-old George, the U.K. media were pondering what it could all mean for the upcoming Scottish independence vote.

Britain Royals

Prince William talks to schoolchildren during a visit in Oxford, England, on Sept. 8, the same day it was announced he and his wife, Kate, are expecting their second child. (Lefteris Pitarakis/Associated Press)

"What's interesting is that on the day of the announcement, the upcoming royal baby has already assumed political significance," says Carolyn Harris, a Toronto-based royal historian and blogger.

The Scottish referendum is just over a week away, and media speculation was swirling Monday "that enthusiasm about a new royal baby might help keep the United Kingdom together," Harris says.

And it's rampant speculation: Even the Guardian newspaper, which has been known to give online readers the chance to opt out of royal coverage with one click, had a poll asking if word of a baby on the way "is the news the No campaign desperately needs?"

Word of Kate's pregnancy came the same day the British pound traded at a 10-month low against the U.S. dollar after a poll suggested 51 per cent support for an independent Scotland in the vote on Sept. 18.

The announcement of the pending birth seems to have been spurred by Kate's acute morning sickness, and the questions that would have arisen over her absence at a planned event Monday in Oxford.

But others took a contrary view about the timing of the announcement in light of the political question looming over Scotland and suggestions that the Queen — the great-grandmother-in-waiting — is quite concerned that Scots may vote to leave the 307-year-old union.

Change your mind?

"There are those cynics, of course, who say 'What timing,'" royal commentator Richard Fitzwilliams told CBC News Network.

"The Royal Family are symbols of togetherness and unity and those who are wavering as to how to vote — and as you know the polls have got so close — they might think again and vote to keep the union if and when they've given it the thought after this very happy, and may I say timely, news."

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William and Kate wave, as the duchess holds her son, Prince George, before they leave Canberra on April 25. (Phil Noble/Reuters)

If the next royal baby does carry some serious political clout, he or she will follow in the footsteps of George, who as a chubby-cheeked nine-month-old charmed adoring fans Down Under earlier this year.

"When William, Kate and George toured Australia and New Zealand, Prince George became known as the 'Republican Slayer,' because support for the monarchy became so high in Australia just 15 years after there'd been a referendum about abolishing the monarchy," says Harris.

"The response to Prince George during his travels in Australia and New Zealand demonstrates that even in the 21st century, a royal baby can have a great deal of political significance."

And because the current political question deals with Scotland, there's an especially rich potential for a historic connection.

"It certainly won't be the first time that the future of Scotland has been tied up with the life of a royal baby," notes Harris.

"Mary, Queen of Scots was only six days old when she succeeded to the Scottish throne, so when we look at Scottish history, there's a whole series of royal children who are politically significant almost from birth."

The heir and the spare

However significant the next royal baby will be, as the younger sibling of a direct heir to the throne, he or she will assume a unique spot in the Royal Family: the "spare" in the oft-used phrase "the heir and the spare."

In the Queen's current reign, the idea of "the spare" has taken on the aura of being a "fun-loving foil to the more dutiful older sibling," Harris notes.

Princess Margaret was spare to her sister, the current Queen. Princess Anne for a few years, and then her younger brother, Prince Andrew, played the spare to William's father, Prince Charles.

And no one has personified the notion of the spare as a more carefree royal than William's younger brother, Prince Harry, who among other antics has been caught on camera frolicking naked at a Las Vegas hotel.

But even if there is an assumption the second child might have more freedom, it may not always be that way.

"Princess Margaret gave up the idea of marriage to the divorced Group Capt. Peter Townsend, even though by the time Peter Townsend proposed to Margaret, the Queen already had two children," says Harris.

"It was less likely that Margaret would ever succeed to the throne, but she still bowed to the royal conventions of the time and ended that relationship."

Fate intervenes

Twists of fate can also propel a younger sibling to the throne.

"Some of the most famous British monarchs never anticipated becoming king or queen," says Harris, quickly rattling off a list that includes Henry VIII, Elizabeth I, Charles I, Anne, George V and the current Queen's father, George VI.

Whatever fate awaits the next baby in the House of Windsor, he or she could anticipate a life with more royal duties than others in a similar position have carried out.

"As an adult, William and Kate's second child may face a very extensive program of royal responsibilities because we're seeing a certain streamlining of the Royal Family," says Harris.

That streamlining was front and centre during the Queen's 2012 Diamond Jubilee celebrations marking 60 years on the throne.

Royal family

Kate, Prince Philip, Camilla, the Duchess of Cornwall, Prince Charles, the Queen, Prince William and Prince Harry participate in the pageant on board the Royal Barge during the Queen's Diamond Jubilee celebrations in June 2012. (Matt Dunham/Associated Press)

"The Diamond Jubilee Thames River pageant emphasized the direct royal line," says Harris, noting the focus on the Queen and Prince Philip; William's father, Charles, and his wife, Camilla; and William, Kate and Harry, rather than the extended family of royal cousins.

While the Queen has been on the throne, those cousins have taken on numerous royal engagements and visits.

"In subsequent reigns we probably will not see that royal extended family doing such a range of engagements," says Harris.

"Members of the Royal Family in the direct line such as both of William and Kate's children are going to find as adults they have quite a busy program of royal responsibilities."

How much they will have to do in Scotland remains to be seen.