This is where France can help. Long ago the French perfected the notion of diplomacy and defense a tous azimuts, that is to say, in all directions. This could make sense for NATO. Rather than alternating between being an existential safeguard and a global expeditionary force, NATO must reassert its primary role as defender of the North Atlantic area, broadly defined. This would make both of the former missions more credible and effective.
De Gaulle contended in 1966 that France could not possess an effective deterrent so long as its troops were under the nominal command of other nations or while the troops of other nations were based on its soil. In other words, boots on the ground and the strategic deterrent were seen as losing parts of a zero-sum calculation.
A similar case could be made today with regard to NATO's forward deployments outside the NATO area. It is not clear how they contribute to the defense of the alliance or deter future attacks upon it, particularly if some members oppose them. No matter how important they may seem to others, they will not work unless they have strong public support and are defensible, as an author of the North Atlantic Treaty, Jack Hickerson, once put it, with a logic that "an Omaha milkman" could understand.
NATO must therefore accommodate its primary mission of defense and deterrence with the more diffuse, collective security identity that it continues to advertise by converting its flexibility from a zero-sum liability into an asset. Ending the theoretical distinction between membership in the alliance and in its military organization is an important step forward.
It might have even made General de Gaulle proud.