March 31, 2025 | CSIS How to secure the Black Sea during a Russia-Ukraine ceasefire Home » Ukraine RADM (Ret.) Mark Montgomery CCTI Senior Director and Senior Fellow March 31, 2025 | CSIS How to secure the Black Sea during a Russia-Ukraine ceasefire RADM (Ret.) Mark Montgomery CCTI Senior Director and Senior Fellow Listen Issues: Issues: Military and Political Power Russia U.S. Defense Policy and Strategy Ukraine