On his recent diplomatic run through Europe, President Joe Biden declared that “America is back” and ready to “engage.” If we are to take him at his word—and we think we should—the administration could take on no better project than forming key action partnerships that nest under the European Union and NATO.

On a national level, countries can take on projects and facilitate cooperation that builds strong superstructures underneath collective defense frameworks and builds trust and confidence between friends and allies. One of the most fruitful partnerships could be joint German-Polish-U.S. cooperation and initiatives.

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The NATO alliance of 30 member nations is grappling with the challenge of adapting to resurgent great power competition with China and Russia. While the United States was at war over the past two decades in secondary theaters, China and Russia were building up their military capabilities.

Now that Washington is increasingly focused on threats emerging in the Indo-Pacific, the task of deterrence and defense along NATO’s eastern flank must progressively fall on the European allies and partners. In this context, political and military cooperation between Germany and Poland, closely supported by the United States, would play a key role in shoring up allied defenses along NATO’s eastern corridor from the Baltic to the Black Sea.

The synergies facilitating such enhanced trilateral cooperation are plain to see. Germany is Europe’s largest economy and also host to the largest American military installations on the continent. Poland is the key country along NATO’s eastern flank, bordering on Belarus and Ukraine—the two states firmly in Moscow’s crosshairs as Putin moves to re-gather the former imperial domain. The largest power on NATO’s Eastern flank, Poland today, is in a position similar to that of West Germany during the Cold War: a country key to NATO’s strategic and operational plans. Germany, meanwhile, is positioned to provide the requisite strategic depth and support, while the U.S. commands core strategic enablers and principal military resources. In a nutshell, a close trilateral U.S.-German-Polish cooperation within NATO would go a long way toward firming up deterrence along the flank, reassuring the Baltic States and enhancing Europe’s security.

While the military piece is relatively straightforward, the political piece will require skill and commitment in Berlin and Warsaw and steady support from the Biden administration. The German-Polish relationship has been rocked by the issue of Nord Stream 2—a project that Berlin has been determined to complete while Poland has openly opposed it. The U.S. decision to consider Nord Stream 2 a fait accompli and partially lift American sanctions on it was welcomed in Berlin but created additional friction in Warsaw, fostering a perception that decisions are being made without consulting the Polish government. The divergence between Germany and Poland on how to deal with Russia going forward can be bridged with strong engagement by the United States.

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One opportunity that could have important economic and security consequences is a joint effort between the three nations to promote investment in the Three Seas Initiative, a project initiated by the Central European countries to promote private sector investment in regional infrastructure. This initiative would not only strengthen NATO’s flank but could spin off into development projects that could benefit both non-NATO and non-EU partners, including Ukraine, Georgia and the Western Balkans.

Biden’s European trip has created an opening to make the political piece work as well. What is needed is a platform for trilateral engagement. Germany, Poland, and the United States can frame the fundamentals of leveraging the geostrategic context to enhance deterrence along NATO's Eastern flank.