Mediaboss Marketing

President Donald Trump walks past French President Emmanuel Macron and German Chancellor Angela Merkel during the NATO summit in Brussels, Belgium, on Thursday. Jonathan Ernst / Reuters

Ahead of Thursday's speech, The New York Times

But his speech stopped short of doing so.

Trump thanked other members for their support following 9/11 "our NATO allies responded swiftly and decisively" but was far from explicit on Article 5.

The president's spokesman, Sean Spicer, told reporters afterward that Trump's mere attendance was a tacit acknowledgement of his commitment to the mutual-defense clause.

"We all understand that by being part of NATO we have treaty obligations and commitments that we made as being part of NATO," Spicer said. "So to have to reaffirm something by the very nature of being here and speaking at a ceremony about it is almost laughable."

Many experts

Any sign that the U.S. might blink first could be taken as a signal by Russian President Vladimir Putin that cracks are appearing in NATO, according to many Western analysts.

"Article 5 is the whole point of NATO," said James Nixey, head of the Russia and Eurasia program at London's

Although talk of all-out-war between America and Russia may seem remote, the possibility that Moscow may try to extend its influence in Eastern Europe had increased in recent years, according to many Kremlin-watchers.

Some of the countries that are now in NATO were formerly part of the Soviet Union, a communist bloc controlled by Moscow whose disintegration Putin has called "a major geopolitical disaster of the century."

The Russian president enjoys sky-high domestic popularity all built on his self-styled image as a man who can restore Russia to its former glory. He sees NATO as a Western encroachment on Russia's borders.

In March, NBC News

Some people living there, around 20 miles from the Russian border, said they felt Trump's ambivalence toward NATO put them in danger of increased Russian influence. They feared a similar fate as Ukraine, which has been fighting rebels

Trump is hardly the first president to press NATO allies to spend more.

NATO recommends that each nation spend 2 percent of its gross domestic product on defense. Only five of the 28 members currently do so the U.S., Greece, Estonia, the U.K. and Poland.

Trump railed against this shortfall Thursday, telling the audience in Brussels that it was "not fair to the people and taxpayers of the United States."

His words echoed those of President Barack Obama, who just last year accused NATO members of being "complacent" and told them to dig deeper into their wallets.

What's different with Trump is that no other president has accompanied this plea with an ultimatum: Pay up or we won't protect you.

Nixey, at Chatham House, agreed that "European states have to pay up more."

But whatever the cost, NATO has always been a trade-off between the U.S. and its smaller allies. Washington protects them and in return gets stability and security along its allied border with Russia and beyond.

"It depends whether you believe that America has a role to play in global security," Nixey said. "If you do, then NATO is critical."

At its heart, the alliance is "all about values," he added. "Most NATO states are committed to democracy. Once you start to undermine the alliance then the whole post-Cold War order breaks down."

Read the rest here:
Donald Trump and NATO: Why His Silence on Article 5 Is a Big Deal - NBCNews.com