Donald Trump has a new royal headache. The next member of the British monarchy is outspoken Los Angeles native and Hollywood actress Meghan Markle, who called Trump "divisive" and "misogynistic." Her fiance, Prince Harry, is also reportedly miffed at Trump's disinterest in human rights. A royal wedding invitation may not be in the offing for the House of Trump.

But the UK royal family is not alone in its crowning criticism. Swedish Princess Madeleine's American husband, Chris O'Neill, openly disrespects Trump, calling him "shameful" and "ignorant." And civilian leaders around the world mock the White House as home to a 21st century American pseudo-monarchy, with German Foreign Minister Sigmar Gabriel earlier this year finding Trump progeny assertively acting "like members of a royal family." Not in a good way.

None of this bodes well for American foreign policy.

If there is a silver lining for the nouveau gilded D.C. leadership, it is in the House of Saud, where a freshly minted king-in-waiting rushes reforms while ridding rivals. Crown Prince Mohammed bin Salman, M.B.S. for short, is praised by some as initiating a managed Saudi "Arab Spring." M.B.S. sees eye-to-eye with a president who practices eye-for-an-eye politics.

Trump son-in-law and Middle East negotiator-in-chief Jared Kushner has been shuttling to Riyadh ever since Trump chose Saudi Arabia for his first official state visit. For Trump, the trip to Saudi was a safe choice for a fragile ego. Trump flew to a kingdom where dissent is illegal and fealty total. As Commerce Secretary Wilbur Ross giddily noted at the time, the visit was unmarred by protest or criticism _ "not one guy with a bad placard."

In Saudi Arabia, Trump was received with deference and respect. The well-coordinated visit, complete with a visually stunning ritual sword dance, paid off for the newly empowered Saudi royals, with M.B.S. seeing his opportunity and seizing a perceived White House greenlight for Riyadh's increasing regional military adventures. POTUS was able to fly away feeling good both about himself and the $1.3 billion arms sale he made to a militarily voracious Saudi kingdom.

Unlike the Saudis, Britain is looking to cut back on its military and arms expenditures. They are also cutting back on the niceties. That makes Britain's royal wedding for the future Duke and Duchess of Sussex an unwelcome irritant for a U.S. president long on style and short on substance.

The smart money would bet that President Trump preemptively suggests he cannot attend Prince Harry's May 2018 wedding, appropriately avoiding personal and national embarrassment. Commentators can be spun to believe that prudent security concerns and likely Trump protests in London would steal the spotlight and spoil the special day and that the president's selflessness should be recognized. Praised, too. It is a tried-and-true Trump tactic, as witnessed by his recent rejection of the TIME "Person of the Year" unawarded recognition. Reject, diminish, deflect, rejoice. Repeat.

Navigating presidential and royal protocol is one thing, dealing with the practical implications of strained relations and policy is another. The United States depends on a strong working relationship with Great Britain to achieve its policy goals around the world. In Afghanistan, for example, where the president has approved and delegated an American troop and bombing escalation, America seeks more British commitments to NATO forces. U.S. troops work side-by-side with UK soldiers who are still part of an in-country foreign military contingent.

Afghanistan may prove to be one of the more challenging war fronts and messaging battles for Donald Trump given that Prince Harry _ unlike White House princelings Donald Trump, Jr. and Eric Trump _ deployed to Helmand province, serving relatively anonymously in the fight against the Taliban and jihadists of all stripes. Should Prince Harry weigh-in on the Afghan war debate, he has serious cred. Trump wants another 1,000 British troops, the UK is reluctantly debating whether to commit another 85.

Any growing and outspoken strain with the House of Windsor is a direct challenge to the historic "special relationship" between Britain and the United States. Further, critical intelligence sharing arrangements have been compromised and diminished by the American president's loose lips. The "Five Eyes" intelligence alliance between Britain and her former colonies Australia, New Zealand, Canada and America, is key in the fight against both state and non-state actors targeting the United States and her strategic interests. As the Five Eyes develop cataracts, the president's "big mouth" _ former White House Communications Director Anthony Scaramucci's characterization _ is getting carelessly louder. As a result, the "special relationship" looks less meaningful and more flighty.

What is replacing this longstanding deep relationship is, instead, a political dalliance between Donald Trump and the UK political right-winger, Brexit-champion Nigel Farage. The president's recent gamboling with the ultranationalist Britain First political organization and his tweeting of their incendiary videos is not helping matters.

Now it is not only Prince Harry who is unimpressed with America's petulant president. Prime Minister Theresa May's government is incensed. Indeed, Britain is becoming a royal pain for Trump.

— Markos Kounalakis, Ph.D. is a senior fellow at Central European University and visiting fellow at the Hoover Institution. Contact him at markos@stanford.edu or on Twitter @KounalakisM.