Denis Staunton outlines how qualified majority voting works
The Council of Ministers has two main ways of taking decisions - unanimity, when everyone has to be in agreement - and qualified majority voting (QMV) - a system of weighted votes. The council uses a simple majority to decide procedural issues.
Qualified majority voting is the most common method of decision-making, used in all but the most sensitive issues. Issues which are decided on by qualified majority are also voted on by the European Parliament. This means that the council and parliament act together in co-decision.
The reason for the qualified majority, rather than a simple 51 per cent, is to ensure that at least half the population of the EU and half the member-states must be in favour of a motion to pass it.
The Nice Treaty makes achieving a qualified majority more difficult by demanding that states representing at least 62 per cent of the EU's population must approve. But it extends the use of qualified majority voting to some policy areas that have until now required unanimity.
Until now, appointments to many senior positions within the EU have required the unanimous approval of all member-states. The Nice Treaty proposes that all members of the Commission, including its President, be chosen by qualified majority.
Member-states will also lose their veto over the appointment of the two most senior bureaucrats in the Council of Ministers and over some external EU representatives.
The treaty extends qualified majority voting to almost all issues concerning trade in services and intellectual property. But it exempts cultural, audiovisual, social, education and public health services.
From 2007, rules governing structural funds will be subject to qualified majority voting, along with other forms of cohesion funding.
Member-states would also lose their national veto over changes to the accounting system for the EU budget.
Decisions on asylum, visas and immigration would no longer be taken unanimously. Ireland and the UK are not subject to common EU rules on asylum and immigration but they may opt in to the EU system if they wish.
The treaty's critics argue that extending qualified majority voting weakens the control national governments exert over the EU.
Its defenders suggest that, in an enlarged EU, unanimity should be required only for constitutional and "quasi-constitutional" issues and questions that affect the institutional balance of the EU, such as official languages.
All questions relating to tax policy will continue to require unanimity.