NATO’s top military officer is reviewing alternative options for defending Europe if Russia were to attack, according to reports from multiple outlets. The review comes after the United States announced it is reducing the number of aircraft and warships it would provide during a security crisis. The coverage indicates that NATO is preparing for different scenarios in light of the expected changes to U.S. contributions. While the details of the specific options being weighed are not described in the reports provided, the thrust is that NATO leadership is looking at how deterrence and collective defense would work under altered support levels from Washington. The U.S. planning shift is framed as part of broader U.S. defense priorities, including the possibility of conflicts elsewhere, which affects the resources available for Europe. Across the sources, the central point is that NATO is conducting contingency planning for European defense in response to a change in anticipated U.S. military assets during a crisis.