Social security systems and social protection
Social security systems provide people with a certain minimum welfare protection. Decisions about social protection and social security systems mostly require unanimity Article 153 TFEU.
Measures aiming at modernising social protection systems can be decided by a qualified majority. Formally, harmonisation of national laws regarding social policy is prohibited.
The EU Court has developed common principles to be followed by all member states. There are three important regulations on social security - 1408 from 1971, 1612 from 1968 and 883 from 2004.
A ruling of the EU Court gives employees working 9 hours per week the right to full social security coverage in all member states.
The Lisbon Treaty considers social policy as a shared competence in Article 4.2b TFEU. EU law therefore override member states' existing legislation and right to legislate exclusively in this area (Article 2.2 TFEU) when the EU takes a decision.
Some social security can be decided by qualified majority under the Lisbon Treaty, with a clause allowing a Prime Minister to waive an original veto at a summit.
Links
European social affairs and equal opportunities:
http://ec.europa.eu/employment_social/index_en.html