FAA MELs have these statements (B717 MMEL):
15. "(M)" symbol indicates a requirement for a specific maintenance procedure which must be accomplished prior to operation with the listed item inoperative. Normally these procedures are accomplished by maintenance personnel; however, other personnel may be qualified and authorized to perform certain functions. Procedures requiring specialized knowledge or skill, or requiring the use of tools or test equipment should be accomplished by maintenance personnel. The satisfactory accomplishment of all maintenance procedures, regardless of who performs them, is the responsibility of the operator.
Appropriate procedures are required to be published as part of the operator's manual or MEL.
16. "(O)" symbol indicates a requirement for a specific operations procedure which must be accomplished in planning for and/or operating with the listed item inoperative. Normally these procedures are accomplished by the flight crew; however, other personnel may be qualified and authorized to perform certain functions. The satisfactory accomplishment of all procedures, regardless of who performs them, is the responsibility of the operator. Appropriate procedures are required to be published as a part of the operator's manual or MEL.
NOTE: The (M) and (O) symbols are required in the operator's MEL unless otherwise authorized by the Administrator.
Here in Australia, our company ops manual authorises the Captain to defer a defect provided there is no (M) action required. You obviously have to comply with the Operations (O) requirements.
Additionally, some items in our MEL are called "FCM", which means Flight Crew Maintenance. In this case, the captain is authorised to defer the defect after doing the FCM.
Example: Gasper fan U/S
MAINTENANCE (M) (FCM)
Pull and collar the associated Gasper Fan circuit breakers, as follows:
GASPER BOOSTER FAN (B1-1170) EPC CBP J-27
GASPER BOOSTER FAN CONTROL (B1-1171) EPC CBP C-3