This refers to a small group of countries able and willing to enter into closer cooperation with one another. This concept has to be seen in the wider context of closer cooperation or flexibility, which could see differentiated integration levels enshrined in the institutional framework of the Union to prevent hard cores from forming outside this framework (as was the case with the Schengen area).
Hierarchy of Community acts (hierarchy of norms)
A declaration annexed to the Treaty on European Union states that "it might be possible to review the classification of Community acts with a view to establishing an appropriate hierarchy between the different categories of act."
The main purpose of such a hierarchy would be to enable the lawmaking authority to concentrate on political aspects of particular issues rather than on questions of detail, which it could delegate to the European or national executives.
Such a hierarchy would help to clarify the Community decision-making process by ensuring that instruments of constitutional status were subject to tougher procedures than legislative instruments, which are themselves subject to tougher procedures than mere implementing acts. The hierarchy of the various acts could also be expressed using the terms describing them.
Community legal instruments
Reinforced qualified majority