The Problem:
Delays in providing troops and equipments as soon as they are needed to help stop a conflict.
This, because some member countries are still walking away from their obligations...
The Social Invention:
Establish a NATO Base (Germany could be a good central location) with plenty of troops (coming from all member countries) and equipments ready for emerging conflicts.
Member countries shall lend troops according to the prorata and/or, give money each year to NATO until troops can be lended again.
Member countries should also give tax breaks to citizens who wish to make donations to NATO. Hence, bringing more cash to maintain and train those troops and furthermore, ease the monetary contribution of a particular country.