A special meeting of NATO heads of state and government in Brussels on May 25 will mark the first occasion for the Allies to meet the new U.S. President Donald Trump.

What’s on the Table

The official program of the NATO leaders has been kept intentionally short and low profile and no real policy deliverables are expected to be put on the agenda. But the meeting is certainly seen with much anticipation in European capitals. Will President Trump outline his vision on the future of transatlantic security and defense cooperation, putting at end a period of ambiguity in U.S.–EU relations?

How it Might Go

For many obvious reasons Europe has looked at the election of Donald Trump with some concern. His statement that NATO was “obsolete” along with his sympathy for Russian President Vladimir Putin shook the traditional vision of Europe’s security architecture to the core. But as Mr. Trump took office his administration has moved swiftly to restore transatlantic trust. Multiple visits to Brussels by senior U.S. officials, including Vice President Mike Pence and Secretary of Defense James Mattis, served to reassure Europeans that “America still has Europe’s back.” Many European NATO Allies now hope to hear at the May 24 meeting the same message from Donald Trump personally.

But the question remains whether something has changed inside transatlantic security and defense relations? President Trump has not hidden his view that NATO must change if the United States is to continue to support the Alliance. When Mr. Trump meets with his European counterparts he is expected to stress two important points.

First, Mr. Trump wants his allies to spend more on defense. And here the U.S. president has a valid point. All NATO allies signed a pledge at the 2014 Wales Summit to spend 2 percent of their GDP on military expenditures by 2024. But despite promises made it seems likely today that a majority of European allies will fail to stand by their word. For Mr. Trump, who was elected on an agenda to “make Europe pay,” this may be a deal-breaker. Europe’s argument that it is sharing the burden in other domains, such as the migration crisis or contributions in Afghanistan, may do little to convince the president. In the long run Europe has to take care of its own defense. As a global power, the United States needs to disperse its forces in many corners of the world and cannot indefinitely account for nearly 73 percent of the total transatlantic defense budget. It is too early to say how Mr. Trump will react if Europe does not increase its financial effort. But all sides have an interest at the NATO meeting to find consensus on what transatlantic burden sharing really means.

Second, Mr. Trump wants NATO to be more engaged in the fight against extremist groups, linked to Islamist terrorism. For NATO, a military organization, this means venturing in new water. History shows that terrorism cannot be fought by planes, bombs, and missiles only. It also requires the right mix of crisis management assets, civil-military cooperation, and human development resources. In this light the Alliance is still struggling to identify for itself a clear role in the fight against terrorism. NATO’s re-engagement with the South is also a key test for the Alliance’s partnerships with many of the key players in the Mediterranean and the Middle East. NATO’s seven-country Mediterranean Dialogue alongside the Istanbul Cooperation Initiative with the Arab Gulf states remains a valuable instrument for security cooperation. But as Donald Trump’s Riyadh speech on May 21st clearly testified a recalibration of U.S. diplomacy in the region, this may affect NATO’s engagement with important regional Alliance partners such as Qatar, Jordan, or Egypt. There is little doubt that in Brussels NATO leaders will have questions from Mr. Trump in this respect.

What is at Stake

The NATO Brussels Meeting on May 24 may be little in scale and ambitions, but it may be instrumental to set the tone in U.S.–EU cooperation for the months and years to come. It marks the beginning of a long-term adaptation of NATO and transatlantic relations in a world that faces disorder for the foreseeable future.