MADRID - Europe's monarchs, long relegated to ceremonial duties, lavish weddings and tabloid gossip fodder, are suddenly on the verge of becoming relevant again.

Spain's King Felipe VI took a leading role in confronting Catalonian separatism when he denounced as outlaws the regional leaders who staged a 2017 independence referendum, asserting the monarchy's constitutional duty to preserve national unity.

And now there is mounting speculation in the British media that Queen Elizabeth II will be called upon to settle a looming constitutional crisis over Prime Minister Boris Johnson's plans to take Britain out of the European Union, if necessary without a deal with Brussels.

Apart from their long moribund constitutional powers, the two monarchs would appear to have little in common.

Elizabeth has spent 67 years on a throne which, for centuries, has been held without interruption by her House of Windsor. Felipe, on the other hand, assumed the crown five years ago through the abdication of his father, whose Bourbon dynasty had been restored by a now-reviled military dictator.

Yet they are blood relatives through Queen Victoria, the British imperial matriarch who wielded political influence throughout Europe and much of the world during the 19th century.

And "both are being called to fill voids created by the inability of elected politicians to grapple with major problems and the high degree of polarization it's engendering," says political science professor William Ogilvie de la Vega of the Franciso Marroquin University in Madrid.

Seeming anachronisms in their highly democratic countries, the two monarchs remain as constitutional heads of state and, as such, hold what former Spanish ambassador to London Federico Trillo-Figueroa describes as "sleeping powers."

These include, in Elizabeth's case, the power to summon and dissolve parliament and to sign legislation into law, though in practice she exercises those powers only at the bequest of the prime minister.

Such powers "are normally exercised in an invisible way and only flower publicly in situations of constitutional crisis to guarantee the equilibrium between institutions," Trillo-Figueroa tells VOA.

But stepping off their royal pedestals to take sides in political slugfests can be a dangerous gamble.

Queen Elizabeth risks alienating the most traditional elements of British society, many of whom voted to leave the EU in a 2015 referendum, if she refuses Johnson's expected request to suspend parliament when they block a no-deal Brexit. Buckingham Palace has already officialy said that the "will of parliament should be respected."

Some days ago, Brexit chief campaigner Nigel Farage launched what for a conservative nationalist politician was an unprecedented attack on the royal family, calling the queen's late mother an "overweight, chain-smoking gin drinker."

King Felipe similarly earned the enmity of Catalan nationalists by openly supporting the imposition of direct rule on Catalonia. Even Barcelona Mayor Ada Colau, who opposes outright independence for Catalonia, shuns the king when the monarch visits in Spain's second largest city. Felipe is invariably met by hostile protests in the Catalan capital.

According to a report in the newspaper El Mundo, former prime minister Mariano Rajoy advised against a royal televised address in which Felipe accused Catalan authorities of acting with "inadmissable disloyalty" before the government formally charged them with sedition and rebellion.

But Raquel Casviner Canellas of the Catalan Civic Union says the king "needed to reassure pro-Spanish unionists who felt that central government responses to the independence challenge had been excessively cautious."

Felipe's father, Juan Carlos, secured the monarchy's survival in Spain by steering the country toward democracy after the death of the dictator Francisco Franco.

He blocked a coup attempt by right-wing officers in 1981, mindful perhaps of how his brother-in-law, Constantine, lost the Greek throne in the 1960s over perceived involvement with a military takeover in Athens.

"The Crowns are resuming their function as the moderating and arbitrational powers that they are characterized to be in modern constitutional parliamentary monarchies," said ambassador Trillo-Figueroa.

There is also evidence of a younger generation of royals being drawn into politics. Prince Harry's Hollywood wife Meghan Markle, Duchess of Sussex, has drawn criticism for gender, racial and political bias in a coming article she edited for British Vogue, titled "Fifteen forces for change."

Of the 15 individuals profiled, "all are women, only five are white," and most represent left-wing causes, according to London's Daily Telegraph.

Britain's Daily Express, meanwhile, notes that former U.S. president Barack Obama is "very close" to Harry and Meghan and offers them advice.