NATO leaders behaved in an “absolutely appalling” way toward President Trump.

That’s what Nile Gardiner, a former aide to the late British prime minister Margaret Thatcher, said when he caught NATO leaders apparently laughing behind Trump’s back when he urged them to “pay their fair share” of the alliance’s defense budget.

Gardiner was outraged when he saw Luxembourg Prime Minister Xavier Bettel flash a catty smirk when Trump said NATO could be even stronger if all member nations paid their fair share for defense.

Their faces say everything:

A whisper & light laugh as Trump uses NATO ceremony to scold members for not paying fair share. pic.twitter.com/jzvuWN8dNi — Sarah Kelly (@SarahKellyTV) May 25, 2017

“Their freedom and security has depended on the U.S. security umbrella for over 70 years,” Gardiner told Fox News.

Gardiner was especially disgusted by French president Emmanuel Macron, who “acted like a little schoolboy.”

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In the 29-nation NATO alliance, total defense spending topped $900 billion in 2015. The United States paid $650 billion, or 73%, of the total budget. The figures were equally lopsided for 2014, and remain so to this day.

Most NATO members haven’t paid their fair share for years. Only five NATO members — the United States, the UK, Poland, Greece and Estonia — have met the treaty’s agreement that nations spend at least 2% of their annual GDP on defense.

The United States spends 3.6% of its GDP toward NATO defense, even though the U.S. provides most of the defense. In contrast, freeloading Luxembourg spends just 0.4%.

President Trump has repeatedly said all NATO members must pay their share if they want the military alliance to continue.

This statement upset some of our NATO “partners” who have become used to mooching off the U.S. But NATO secretary general Jens Stoltenberg said Trump raised a valid point.

“We agree that the alliance needs to redouble their efforts to meet the pledge we all made in 2014 to invest more in our alliance,” Stoltenberg said. “This means cash, capabilities and contributions. Fair burden-sharing has been my top priority since taking office.”

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