Editor's Note: (Frida Ghitis is a world affairs columnist for The Miami Herald and World Politics Review, and a former CNN producer and correspondent. The views expressed in this commentary are her own. This commentary has been updated from an earlier version.)

(CNN) Donald Trump's peculiar relationship with the truth -- his penchant for promoting unfounded stories and conspiracies theories -- represents not just a curious quirk or a character flaw. They are a much-practiced technique that has paid dividends as self-promotion in his business career and in his political rise. Over decades spent in the company of yes men and yes women, he has been able to fire off nonsense without question or rebuke.

But now he is President Trump, and his breezy spewing of falsehoods has become a national embarrassment --a threat to U.S. security and America's standing in the world.

White House officials have just had to apologize to the United Kingdom for smearing the British intelligence agency by making false statements . This is a sign of things to come.

Indeed questions about Trump's wiretapping allegations against Barack Obama, and Press Secretary Sean Spicer's regurgitation of Fox News commentary, came up during Trump's press conference with German Chancellor Angela Merkel Friday--further evidence that the rest of the world is paying attention. He took no responsibility and said if there were questions about the allegation, people should ask Fox News about it.

What should concern every citizen is that Trump's crumbling credibility will not be limited to him. America itself is losing credibility. If the president of the United States cannot be taken at his word, America's arguments on the global stage will be easily dismissed. This will have profound and very specific consequences as the country faces new and old challenges, which will require the support of other nations.

That became clear in the latest chapter in the bizarre story of Trump's claim that Obama ordered the wiretapping of Trump Tower. The accusation, which would be extraordinarily grave if it contained a shred of truth, has been denied by intelligence officials and discredited by well-informed Democrats and Republicans. And yet, on Thursday, Trump had sent Press Secretary Sean Spicer to do battle with the truth once again.

Presumably following his boss's instructions, Spicer proceeded to repeat yet another unfounded rumor, this one slandering America's top ally, the United Kingdom. He read a claim by Fox News commentator Andrew Napolitano that Obama maneuvered around US agencies by partnering with GCHQ, the secretive British intelligence agency, to spy on Trump.

The British, not surprisingly, were furious. The phones in the White House started ringing immediately after the press briefing. The Trump administration had triggered a wholly unnecessary diplomatic crisis by once again treating the truth with casual contempt.

Now Spicer and National Security Advisor HR McMaster have been forced to apologize to Britain, and the British have made sure the whole world knows the White House is making "ridiculous" statements. It is hard to overemphasize the significance of GCHQ, which almost never speaks out publicly, calling the claims "nonsense." The spokesman for the British prime minister said the White House promised to never repeat the false allegations.

The British are right to feel indignant. The two countries have partnered for decades, supporting each other on battle fields, on intelligence and on global diplomacy. Prime Minister Teresa May has taken political risks by being one of the first foreign leaders to align herself with Trump. Now the Trump administration made an assertion that, like most libelous rumors, will never be completely erased in some people's minds. And it did so to score political points domestically.

It's sadly ironic that after less than two months in office, Trump, who often criticized Obama for making legitimate apologies for America's historical misdeeds -- "We will stop apologizing," Trump declared -- had to send his deputies to apologize for brand new, unnecessary and deeply personal missteps.

It's easy to say why Trump plays games with the truth. By claiming that factual reports are "fake news," he undermines the credibility of his critics. By "gaslighting," the country, blurring the lines between fact and fiction, he gets to write his own version of the truth. And by putting out shocking conspiracy tales and wild allegations, he changes the subject at just the right time.

The wiretapping tweet successfully knocked out of the headlines discussion over whether Attorney General Jeff Sessions committed perjury when he falsely told a Senate committee that he had no contacts with Russians.

But maneuvers that may help Trump politically hurt America on the global stage. The lying alone has already eroded America's moral authority, which is arguably the country's most powerful, least expensive weapon and the impetus for persuading others to follow its lead. What will happen when the U.S. needs support to impose economic sanctions or perhaps an arms embargo?

Strong, credible arguments can help America avoid costly wars, just as the wrong words, ill-conceived provocations, can trigger conflicts, putting American soldiers in harm's way and US citizens in peril.

America's strength is not just its mighty military or its giant economy. The United States is strong also because it has allies that will side with it on difficult challenges. But to persuade others that the challenges are real, Washington must have credibility, and Trump is squandering America's credibility, discarding it as if it were the leftovers at a Mar-a-Lago brunch buffet.

Trump may not care about the truth, but the rest of the world does. America's allies do. It's about time for the President and his staff to understand that this is no game. They cannot repeat statements they hear on television, unless they know they are factual. To do otherwise could trigger potentially grave consequences.

If Trump wants to go down in history as a successful president, it's time for him to re-examine his relationship with the truth.