WASHINGTON ― While one of the two top contenders for the presidency of the United States has spent weeks exploring ways to throw America’s allies under the bus, the U.S.’s most important international partnership, the NATO alliance, has been hard at work.

NATO held its latest major summit in July, a few days before Republican presidential nominee Donald Trump said his potential administration would not necessarily defend the alliance’s members against an invasion.

For now, under President Barack Obama, the U.S. commitment to the alliance remains unquestioned. And that’s key for a top American priority: working out a way to stabilize Afghanistan, so that U.S. troops can come home and the country can be kept from again becoming a haven for international militants. NATO immediately offered Washington support after 9/11 and helped the U.S. weed Al Qaeda out of Afghanistan. Its latest summit produced a commitment to share the burden of funding the country’s security forces until 2020.

Peter Wittig, Germany’s ambassador to the U.S., spoke to The Huffington Post around the time of the summit about the other priorities for the alliance, of which his country is one of the most important members.

“NATO has two challenges today. One is in the east and one is in the south,” Wittig said, alluding to Russia’s growing threats to NATO members in eastern Europe and the refugee crisis in southern Europe, which the alliance is trying to combat through military patrols to deter smugglers, as well as financial and infrastructure support for refugee-producing countries.

“We need to show resolve in our relations to Russia to reassure our eastern partners in NATO,” the ambassador continued. “After the annexation of Crimea, after the conflict in eastern Ukraine, they are scared and we need to reassure, and so we have strengthened our persistent presence.”

Germany is one of 4 NATO nations which will now post battalions in the eastern European countries of Lithuania, Latvia, Estonia and Poland to deter Russian belligerence. The other contributing members are the U.S., United Kingdom and Canada.

“This is a visible sign that NATO and those countries in particular who are leading those brigades have stakes and underpin the reassurance with their own troops,” Wittig said.

The alliance wants to ensure that article 5 of its founding treaty, which guarantees that all members will defend one if it is attacked, is meaningful for even the smallest of its 28 members.

This is the aspect of it that Trump and his supporters object to. The potential president says that before defending a NATO ally of the U.S., he will check whether that country has recently met the alliance’s requirements for defense spending.

Each member country is meant to spend at least 2 percent of its budget on the military. Many European nations have failed to meet that target, but Germany and others are now starting to break that pattern.

Supporters of NATO in the U.S. don’t often make that point in defending the alliance. Democratic presidential nominee Hillary Clinton and her allies in the Obama administration are calling Trump’s comments unfit, but they aren’t fully explaining why NATO readiness and maintaining U.S. friendships abroad is essential for American security.

This is an oversight in a year when both loud voices on the right that support Trump and increasingly prominent figures on the left are bashing the alliance.

War-weary Americans love the argument that NATO is a quasi-imperial, militaristic force that’s likely to ignite conflict for unnecessary reasons. That means supporters of the alliance need to explain why they see its strength as critical to encouraging peace in Europe ― and answer critics who say NATO was heavy-handed in expanding throughout former Soviet territory and is unable to have a dialogue with Russian President Vladimir Putin. Putin himself has little incentive to work with the alliance, given that it’s a convenient foreign bogeyman to blame for the decline of Russia under his rule, so he focuses on exploiting divisions within the alliance and using Russian media to tarnish its image. NATO supporters need to explain how presenting a united front helps change Moscow’s calculus.

Public opinion surveys in Europe should serve as a warning for them: many Europeans appear uninterested in the mutual security aspect of the alliance, and are keen to see the U.S. work on its own to help countries threatened by Russia. This is not so different from what Trump and far-left NATO critics argue: let someone else deal with the threat, even if these countries are our friends.

Germany’s government is keenly aware of how popular opinion makes it difficult to justify defense spending on NATO, Wittig indicated, due to general war-weariness and Germany’s specific history. The ambassador emphasized that strengthening NATO must be part of trying to entrench peace.

“Inextricably linked to deterrence is dialogue,” Wittig said. “It’s important not to break off the bridges with Russia but speak to each other.” The German diplomat said communicating with Russia would be key for NATO’s handling of crises like the war in Syria.

“We want to restore our more cooperative relationship with Russia,” he added.

That final reference to the scope of issues the alliance touches is something NATO-bashers miss: There is a lot more on NATO’s radar than Moscow-backed fighters in eastern Ukraine.

Though Trump continually tells Americans the organization is not part of the battle against the self-described Islamic State group, NATO has been training Iraqi forces who are central to defeating ISIS and now plans to collect and share more intelligence on Middle East militancy. (The alliance is planning to appoint a top intelligence official, a move Trump lied about and said was a direct result of his criticism.) The alliance was also central to the widely misunderstood humanitarian intervention in Libya in 2011. And it is pushing forward on cyber-security for member countries, addressing a concern that’s grown in the U.S. since major hacks linked to Russia and North Korea.

Far from the campaign trail, these are clear signs of how the alliance currently serves the U.S. ― and how great a burden Americans would take on alone if Washington begins to back away from its relationships come January 2017.

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims ― 1.6 billion members of an entire religion ― from entering the U.S.