Donald Trump's constant refrain to European allies to "spend more" on defense is usually accompanied by a demand to "do more" on counterterrorism. And the US president has made clear he's expecting to be served a platter of plumped-up policies at the NATO summit in July. US Ambassador to NATO Kay Bailey Hutchison confirmed Wednesday that's "definitely" something Trump is seeking as a summit "deliverable."

Although it was the terrorist attack on the US on September 11, 2001 that remains the sole time NATO's sacred Article V — collective defense — has ever been invoked, it was only Russia's 2014 annexation of Crimea and its brash buildup in eastern Ukraine that galvanized the alliance to dramatically reform and reconfigure itself.

Read more: Can the trans-Atlantic relationship survive Donald Trump?

Counterterrorism has not traditionally been one of NATO's core tasks, in no small part because it's a capacity that lies primarily with national governments and their intelligence, law enforcement and police services. 

NATO says it's 'stepping up' 

Nonetheless, the alliance feels it has a long and laudable list of achievements officials repeat whenever questioned about Trump's demands. These include becoming a full member of the US-led global coalition fighting "Islamic State," in addition to providing AWACS flights, creating a "terrorism intelligence cell" at headquarters, along with a regional "hub for the south" at NATO's Joint Force Command in Naples to provide extra visibility and maneuverability in that area.

Add to these the now 17-year-long war to wipe out terrorist havens in Afghanistan and the training program for Iraqi security and defense forces that will be formally expanded at the July summit.

Elisabeth Braw, a senior fellow with the Atlantic Council, believes the US should be satisifed.

"Since the alliance is extremely busy simply trying to address purely military challenges, now is not the best time to be pushing members to also focus more on terrorism," she told DW. "What's more, it's not clear how counterterrorism would become more effective by shifting more tasks to NATO. Law enforcement agencies are already doing a good job."

Read more: How does Germany contribute to NATO? 

Caliphate gone, but challenge remains

Former commanding general of US Army Europe Ben Hodges, however, told DW he agrees more focus is warranted. "I think the alliance needs to put more attention on the Black Sea region similar to what it's done with the Baltic region as part of a coherent defense strategy," explained Hodges, now retired and with the Center for European Policy Analysis. "We don't get to choose our threats," he added. "It's not either [Russia] or [IS]."

Ian Lesser, executive director of the German Marshall Fund's Transatlantic Center in Brussels, agrees, pointing out that polls on public threat perception demonstrate that in the majority of NATO nations, Russia doesn't top the list of perceived threats. Risks "from the south," including IS but also mass migration, are in many cases much more prominent. "That isn't just true for countries in southern Europe," Lesser told DW. "It's also true for France; it's arguably true for Germany."

Lesser explained the south is quite a logistical challenge compared with the single — and obvious — adversary in Europe's east. "The sources of instability are multiple, and it's an enormous geographic expanse that involves both land and sea space stretching across thousands of kilometers," Lesser pointed out. "So it's also a theater in which it's extremely important to have effective cooperation with other partner states but also partner institutions, the European Union and others."

EU-NATO fighting radicalization at its roots

That's where something new is in fact happening, since the EU and NATO agreed to intensify cooperation at the alliance's Warsaw summit in 2016. The first EU-NATO staff-to-staff dialogue on counterterrorism took place on May 29. Michael Kohler, director for EU-Neighborhood Policy at the EU's directorate for development cooperation, told DW that for the first time the EU is contributing money to a program run by NATO called "Building Integrity," which conducts training and exercises in transparency and accountability to combat corruption in defense and security sectors in a range of partner countries. 

It may be the slow road in fighting terrorism, but Kohler believes efforts like this are the most sustainable and effective. "[If] you don't have a government that creates chances for the younger generation, there's an awful lot of frustration and in some cases this frustration will spill over into radicalization," he explained. "So in other words, if you really want to do something against terrorism, you have to treat the symptoms, but you also have to cure the root causes."

Will programs like that satisfy the US president? Ian Bond, director of foreign policy for the Center for European Reform, suspects some of Trump's insistence that NATO isn't doing enough is because he doesn't understand how the alliance works.

"NATO is not going to start picking up random people who've been radicalized on the internet and want to blow themselves up," Bond told DW. "You're not going to deploy NATO's rapid-reaction force to a guy with a van and some knives on London Bridge. NATO is not the answer to most of the kinds of terrorism that western countries are now facing."