It’s been six years since Russia annexed Crimea, the first time since 1945 that European borders were changed through military force. The annexation halved Ukraine’s coastline and, along with the subsequent deployment of anti-ship and anti-air missiles, advanced Moscow’s big geostrategic goal of turning the Black Sea into a Russian-controlled lake. 

This is a direct threat to U.S. and NATO security interests. The Black Sea has long been a geopolitically and economically important crossroads between Europe, Asia, and the Caucasus. Today, the sea’s floor is crisscrossed with oil and gas pipelines and fiber optic cables. Three of the six Black Sea countries—Turkey, Bulgaria and Romania—are in NATO. Another two—alliance partners and aspiring members Ukraine and Georgia—have suffered the direct impact of Russian aggression. Ukrainian solders die fighting for their country every week. One-fifth of Georgia’s internationally recognized territory is under Russian occupation, including a sizeable amount of Georgia’s Black Sea coastline. 

Soon after Russia’s invasion of Ukraine, the United States and several other NATO members stepped up their presence in the Black Sea. But that presence waned, and notwithstanding Secretary-General Jens Stoltenberg’s 2017 pledge to send more alliance ships to the region, it remains insufficient.

Part of the problem is the 1936 Montreux Convention, which limits the number, transit time, and tonnage of naval ships from non-Black Sea countries that may operate in the Bosphorus. For example, non-Black Sea state warships in the strait must not displace more than 15,000 tons apiece. No more than nine non-Black Sea state warships, with a total aggregate tonnage of no more than 45,000 tons, may pass at any one time, and they are permitted to stay for no longer than 21 days. To be sure, NATO navies have shrunk since the Cold War, reducing the number available for Black Sea operations. Yet the limits remain a problem nonetheless.

There are four creative ways that the Alliance should consider to get around these restrictions and increase its presence in the Black Sea:

1. Establish a Black Sea Maritime Patrol mission modeled on the successful Baltic Air Policing mission, in which non-Black Sea members would commit to a regular and rotational maritime presence in the Black Sea. This would be the fastest and most effective way to increase NATO’s presence there, but a lack of political will, coupled with the reduced size of Europeans navies, makes it unlikely.

2. Germany’s Danube option. According to Article 30 of the 1948 Convention Regarding the Regime of Navigation on the Danube, only Danubian countries can operate naval vessels in the Danube River. However, if a Danubian country wants to enter a stretch of the Danube River falling outside its territorial jurisdiction, then it must first get the permission of the relevant Danubian state. 

As the Romanians routinely show with their three frigates, warships of 8,000 tons or less can travel 50 miles upriver to the port of Braila. The only Danubian country that is not on the Black Sea, but still has a navy, is Germany. Therefore, by Romania inviting Germany into its section of the Danube River, it would allow the German Navy reset the clock on the 21-day limit.

Last year, Germany sent just one ship—a 3,500-ton Elbe-class tender—into the Black Sea for a total of only 18 days. This Danube option, unique to Germany because it is a Danubian state, would allow it to step up the plate in a way other members of the Alliance cannot in the Black Sea.

3. The Danube-Black Sea Canal option. This man-made canal in Romania might offer an opportunity for non-Danubian and non-Black Sea states to reset the clock on the 21-day limit in the Black Sea in a similar way that Germany could do so using the Danube River. However, the canal is relatively small at 90 meters wide and can only handle ships up to 5,000 tons.

In 2019, a total of 13 naval vessels displacing less than 5,000 tons from Canada, France, Spain, Italy, Greece, the U.S. and the U.K. entered the Black Sea in ships that could, in theory, operate in the canal. However, this option would likely require money to modernize and adapt the canal for duel civilian-military use. Also, force protection measures such as air defense capabilities would need to be considered. NATO should work with Romania to conduct a feasibility assessment on the possibility of using the canal.

4. A NATO-certified Center of Excellence on Black Sea Security in Georgia. There is no precedent for such a center in a non-NATO country, but there is nothing practically or legally preventing it from happening. Establishing one could improve NATO-Georgia relations while demonstrating how important the Black Sea region has become for Europe’s overall security. The Center would provide an opportunity to engage in meaningful dialogue and training in how to address the challenges associated with Black Sea security. It was also serve as another way to fly the NATO flag in Georgia.

Some of these proposals are easier than others. Some would require only additional political will. Some are unconventional and would require a change in traditional thinking. Some might require additional funding.

All of these proposals require full involvement and consultation with Turkey, the NATO member with sovereign control of the straits. It should be explained to Ankara that nothing NATO will do in the Black Sea is meant to undermine this control. The goal is to increase NATO’s presence in the Black Sea to deter, and if required defeat, Russian aggression.

One might reasonably ask about the feasibility of placing a very expensive warship into a narrow canal or river. There are three reasons why this is not an issue.

First, any ship entering the Black Sea has to travel through a very narrow body of water anyway. At its narrowest point, the Bosphorus Strait is 700 meters wide. This strait is also very congested, with civilian maritime traffic reducing maneuverability even more.

Secondly, ships using the Bosphorus are prohibited from launching aircraft while transiting. This makes air defense and other force protections measures that are routine when a warship transits through a narrow body of water more difficult. This would not be a problem on the Danube River or the Black Sea-Danube Canal.

Finally, the use of the Danube River or the canal would only be done during peacetime. After all, during a time of war Turkey has even more control over the entry and exit of the Black Sea. 

While NATO’s interest in Black Sea security is increasing, the overall presence of non-Black Sea NATO warships is not keeping up the pace. Something needs to change. The economic, security, and political importance of the Black Sea and the broader region is only becoming more important. NATO members need to be protected. The Alliance needs to chart a path to membership for Georgia and Ukraine. NATO must be prepared for any contingency with Russia.

The Alliance is required to defend Sofia and Bucharest in the same way it must defend Seville and Brussels. Just because the geo-political circumstances of the Black Sea make NATO’s mission there harder, does not mean the region can be ignored. With Russia increasing its military capability in the region, now is not the time for NATO to grow complacent.

Until NATO starts thinking creatively about complex challenges like increasing its presence in the Black Sea, Russia will continue to have the upper hand.