What concerns do Europeans and Zelensky have regarding potential U.S.-Russia negotiations over Ukraine?

According to Dov Zakheim, former Under Secretary of Defense, both Europeans and many in Washington are deeply troubled by the prospect of direct U.S.-Russia negotiations that exclude Ukraine. President Zelensky is described as 'terrified' that such talks could result in territorial concessions without his input. Zelensky's primary fear is that 'a deal will be cut' where he would 'lose part of his country.' This scenario represents a nightmare for European nations who see parallels to historical appeasement policies and worry about their own security guarantees. The situation highlights growing anxiety about Western commitment to Ukraine's territorial integrity amid shifting geopolitical dynamics.