Penrose Method - The EU Proposal

The EU Proposal

See also: Voting in the Council of the European Union

Comparison of voting weights
Population in millions as of 1 January 2003

Member state	Population		Nice		Penrose
Germany	82.54m	16.5%	29	8.4%	9.55%
France	59.64m	12.9%	29	8.4%	8.11%
UK	59.33m	12.4%	29	8.4%	8.09%
Italy	57.32m	12.0%	29	8.4%	7.95%
Spain	41.55m	9.0%	27	7.8%	6.78%
Poland	38.22m	7.6%	27	7.8%	6.49%
Romania	21.77m	4.3%	14	4.1%	4.91%
Netherlands	16.19m	3.3%	13	3.8%	4.22%
Greece	11.01m	2.2%	12	3.5%	3.49%
Portugal	10.41m	2.1%	12	3.5%	3.39%
Belgium	10.36m	2.1%	12	3.5%	3.38%
Czech Rep.	10.20m	2.1%	12	3.5%	3.35%
Hungary	10.14m	2.0%	12	3.5%	3.34%
Sweden	8.94m	1.9%	10	2.9%	3.14%
Austria	8.08m	1.7%	10	2.9%	2.98%
Bulgaria	7.85m	1.5%	10	2.9%	2.94%
Denmark	5.38m	1.1%	7	2.0%	2.44%
Slovakia	5.38m	1.1%	7	2.0%	2.44%
Finland	5.21m	1.1%	7	2.0%	2.39%
Ireland	3.96m	0.9%	7	2.0%	2.09%
Lithuania	3.46m	0.7%	7	2.0%	1.95%
Latvia	2.33m	0.5%	4	1.2%	1.61%
Slovenia	2.00m	0.4%	4	1.2%	1.48%
Estonia	1.36m	0.3%	4	1.2%	1.23%
Cyprus	0.72m	0.2%	4	1.2%	0.89%
Luxembourg	0.45m	0.1%	4	1.2%	0.70%
Malta	0.40m	0.1%	3	0.9%	0.66%
EU	484.20m	100%	345	100%	100%

The Penrose method became revitalised within the European Union when it was proposed by Sweden in 2003 amid negotiations on the Amsterdam Treaty and by Poland June 2007 during summit on the Treaty of Lisbon. In this context, the method was proposed to compute voting weights of member states in the Council of the European Union.

Currently, the voting in the Council of the EU does not follow the Penrose method. Instead, the rules of the Nice Treaty are effective between 2004 and 2014, under certain conditions until 2017. The associated voting weights are compared in the table to the right along with the population data of the member states.

Besides the voting weight, the voting power (i.e., the Penrose–Banzhaf index) of a member state also depends on the threshold percentage needed to make a decision. Smaller percentages work in favor of larger states. For example, if one state has 30% of the total voting weights while the threshold for decision making is at 29%, this state will have 100% voting power (i.e., an index of 1). For the EU-27, an optimal threshold, at which the voting powers of all citizens in any member state are almost equal, has been computed at about 61.6%.. After the university of the authors of this paper, this system is referred to as the "Jagiellonian Compromise". Optimal threshold decreases with the number of the member states as .