Trump Tells NATO to Pay Up for Military

President’s lack of public support for common defense provision rankles European allies.

President Donald Trump on Thursday issued tough new spending demands for the North Atlantic Treaty Organization while withholding public support for a core tenet of the security alliance that an attack on one member nation is an attack on all.

The absence of an explicit endorsement of NATO’s common defense provision, known as Article 5, left European diplomats dismayed, stoking tensions that had arisen during last year’s presidential campaign.

As a candidate, Mr. Trump described NATO as obsolete and said the alliance should focus more on terrorism and Europe should pay more for its defense. He suggested that U.S. support for allies could be conditioned on their military spending.

Heading into this week’s NATO meeting, allies said they had hoped Mr. Trump would put to rest worries raised during the campaign that American support for Europe was conditional.

European allies have, sometimes reluctantly, embraced the Trump administration’s call to focus more on counterterrorism and dedicate additional defense spending to filling capability gaps. NATO Secretary-General Jens Stoltenberg has prodded European allies to raise spending and reassured them about America’s commitment to the alliance.

By not putting aside lingering questions about America’s support for NATO, Mr. Trump may have made it more difficult to advance his counterterrorism agenda.

“I think he has undermined his ability to lead,” said Ivo Daalder, a former NATO ambassador. “Leadership is effective only if you have followers.”

More From The Wall Street Journal (subscription required):