With a handful of frozen conflicts, hybrid warfare, rising autocracy, and political instability, the Black Sea region may be Europe’s most volatile and most overlooked.

This week, policy experts are testifying in Congress and calling for the United States to step up its involvement in the Black Sea region, a critical geopolitical crossroads where U.S. allies and adversaries coexist.

“The region is Europe’s most contested domain,” said Ian Brzezinski, a former deputy assistant Defense secretary for Europe and NATO who testified to Congress on Wednesday.

“It’s where you have the most intense confrontation and the most violent conflict in Europe in the last decade and a half. It’s high time we start addressing what needs to be done to bring greater peace and stability to that region,” Brzezinski told National Journal.

Last week, Russian fighter jets intercepted two U.S. bombers over the Black Sea while Defense Secretary Lloyd Austin was visiting Romania, a member of the European Union and a NATO ally that hosts nearly 1,000 U.S. servicemembers. During his trip, Austin also visited two other Black Sea countries, Georgia and Ukraine, a move many saw as a sign that the U.S. was beginning to focus on the region ahead of a key NATO ministerial meeting.

High on the agenda during Wednesday’s congressional hearing, however, was the U.S. relationship with Turkey, a NATO ally that under President Recep Tayyip Erdoğan has had an increasingly fraught relationship with the West. Despite being part of the Western military alliance, Turkey has consistently opposed strengthening NATO’s presence in the Black Sea and courted Russia, opting to purchase a Russian missile-defense system that military experts say poses a risk to NATO equipment.

“We have got to repair our relationship with Turkey. It’s not impossible. Erdoğan is a deal-maker,” said Jim Townsend, a senior fellow at the Center for a New American Security and former deputy assistant Defense secretary European and NATO policy, who also testified Wednesday.

Over the weekend, Erdoğan ordered the country’s Foreign Ministry to declare 10 ambassadors, including the U.S. ambassador to Turkey, persona non grata after they called for the release of an imprisoned civil-society leader named Osman Kavala. Erdoğan later walked back the statement, but the incident highlighted the volatility of Turkey’s relationship with the West.

“Because Turkey is pursuing its own Russia-friendly policy and is often antagonistic towards the U.S., that makes our Black Sea policy so much more difficult,” said Ariel Cohen, a senior fellow at the Atlantic Council’s Eurasia Center, who argues that NATO allies should be more active in the region.

Sen. Ben Cardin, the chair of the Helsinki Commission, said the U.S. and Turkey share many interests in the Black Sea region but that shouldn’t stop Washington from speaking out on human rights.

“Mr. Kavala, a Turkish philanthropist, has been in detention for four years despite being acquitted by a Turkish court,” Cardin said in an email. “In their joint statement, the ambassadors simply asked that Turkey adhere to its international obligations and domestic law.

“This kind of straight talk is important among NATO allies and did not warrant such a disproportionate response.”

Despite the tensions with Turkey, Russia is the primary adversary in the region. Many lawmakers note that Moscow has trampled the rules-based international order by invading its neighbors and propping up separatists to prevent countries along the Black Sea from forming closer ties with the West.

Russian forces currently occupy around 20 percent of Georgian territory and support separatists in the breakaway regions of Abkhazia and South Ossetia. They also annexed Ukraine’s Crimean Peninsula in 2014—in large part to maintain access to the Black Sea—and support pro-Russian separatists in Eastern Ukraine.

Sen. Jeanne Shaheen, chair of the Senate Foreign Relations subcommittee on Europe, said she convened Wednesday’s hearing to learn how lawmakers can holistically approach the region to address patterns of Russian encroachment.

“Over the last two decades, the Black Sea has become an increasingly important region for Russia, which has repeatedly disregarded international norms to expand control of the region, waging war and deploying illegal and belligerent tactics to secure these goals,” Shaheen told National Journal. “Russia has made it clear that it is willing to exert economic, military, and political power to thwart NATO expansion and expand its control in the Black Sea.”

Experts are arriving in Congress with a laundry list of recommendations, including building up Bulgaria’s and Romania’s navies, sending brigade combat teams to both countries, investing in initiatives to counter Russian disinformation, and providing Ukraine with more lethal weaponry. Some are advocating for the creation of a NATO readiness action plan for the Black Sea, and for moving forward with NATO membership for Ukraine and Georgia.

Both countries are angling to join the Western military alliance. Still, the alliance’s commitment to collective defense prevents countries already in a state of conflict from entering, a fact that Russia exploits.

Because Georgia is not yet a NATO member, the U.S. recently renewed a six-year security pact with Tbilisi designed to bolster the defense capabilities of the country’s military. The U.S. is moving away from training battalions in Georgia and will focus instead on building sustainable institutional capabilities at the executive levels of the military.

Still, experts warn that nearly all the countries in the region are dealing with political instability, Russian interference, or both.

Georgia, heading for a second round of local elections on Saturday, has been accused of Democratic backsliding. Romania and Bulgaria, both EU members, are also in contentious election cycles and debates over government formation that will determine their future political trajectories.

Ruslan Trad, an author researching Russian influence in Bulgaria, told National Journal there are several popular pro-Russian political movements in Bulgaria. Russian spies are active in the country and allegedly monitored European Union leaders during their visits. There’s also an urgent need to counter Russian disinformation and anti-NATO propaganda in the country, Trad said.

What’s most important, said Ben Hodges, a retired lieutenant general now at the Center for European Policy Analysis, is to have a robust strategy for the entire region.

“Having a strategy for the region has to be the first priority because then you can develop the right policies for each of the countries in the region,” Hodges said.

The Biden administration is now working on a global-force-posture review, which should shed light on U.S. policy towards the region, and the State Department is also developing a Black Sea strategy.

Alina Polyakova, the president of CEPA and another witness in Wednesday’s hearing, said it would be important to pinpoint the specific areas in which each partner country in the region can contribute to broader security.

“The Black Sea region is critical to broader transatlantic stability,” Polyakova told senators. “It is where Russia, Europe, the Middle East, the Balkans, and the Caucasus come together, and it’s also the locus of the Kremlin’s test of the alliance’s credibility and resolve.”