While much hinges on Trump’s cabinet picks, thus far he has repeatedly questioned Article 5 of NATO’s founding treaty, which stipulates that an attack on one ally is an attack on all of them. He has discussed leaving NATO members on their own to defend themselves if they don’t pay more for their own defense, refused to answer whether he would categorically defend the Baltic states in the event of a Russian incursion, and has called for a reset of relations with Putin. Lieutenant General Michael Flynn, his national security adviser, has dined with the Russian leader, and appeared as a commentator on Russian state television; K.T. MacFarland, Trump’s deputy national security adviser, suggested that Putin deserves a Nobel Peace Prize. Donald Trump, Jr., meanwhile, recently met with a Syrian politician who happens to be close with Russian Foreign Minister Sergei Lavrov, and is widely believed to support the regime of Bashar al-Assad in Syria.

Michal Baranowski, director of the German Marshall Fund in Warsaw, said that for many European leaders, “there is some merit in continuing with the narrative of ‘let's wait and see,’ which doesn’t exclude preparations for ‘Plan B.’” The Baltic states of Estonia, Latvia, and Lithuania, which won independence from the Soviet Union in 1991 and joined the EU and NATO in 2004, are acutely aware of how dangerous a ‘Plan B’ might be, accustomed as they are to coming under the spotlight when U.S.-Russia relations come under strain. Since Trump’s victory, speculation has resurfaced that Latvia, which has a sizeable ethnic Russian population and recently ramped up its military preparations, could be Putin’s next target.

Like many security officials in the region, Jonatan Vseviov, permanent secretary of the Estonian ministry of defense, was circumspect. “Every campaign is heated. I’m sure it’s going to be fine,” he said, echoing a now-common sentiment across Eastern Europe. “There is no causal relationship, necessarily, between relations between the U.S. and Russia, and Baltic security. I don’t think we live in that simple a world,” he said. “We live in a region that is very stable, but where stability can turn into instability relatively fast.”

More than any other nation in the region, Estonia has tried to demonstrate that it is contributing its share to the alliance. Juri Ratas, the country’s new prime minister, promised last week to continue investing at least 2 percent of GDP on defense spending, the target for NATO member states; Estonia also plans to exceed 2 percent next year. Many nations contribute just under the 2 percent threshold: In 2015, only Estonia and Poland met it. Latvia, Lithuania, and Romania have, however, been gradually increasing their defense expenditures in recent years.

But just in case Trump does refuse to honor America’s commitments to its NATO allies, or cuts a deal with Russia that leaves European nations on the periphery vulnerable, some leaders are exploring other options. Polish President Andrzej Duda, for one, is hoping to resurrect the post-World War I concept of a Central European Intermarium, an alliance of nations spanning the Adriatic, Baltic, and Black Seas, that could serve as a counterweight to growing Russian and German power. Most conceptions of such an alliance include the Baltic states, the “Visegrad Four”—Poland, Hungary, the Czech Republic, and Slovakia—as well as Romania, Bulgaria, and several Balkan nations. Last year, the bloc met in Bucharest to discuss concerns about Russian aggression.