Bermuda is the largest overseas territory of Great Britain. Queen Elizabeth II is the Head of State. Through the Governor of Bermuda, Great Britain oversees areas like Bermuda’s defense, external affairs, external trade relations and internal security. Bermuda is otherwise autonomous and self governing. Bermuda's parliament is structured in a way quite similar to the Westminster Parliamentary system in the UK. Bermuda's constitution was first introduced on June 6, 1968.
Since then, there have been general elections contested by the political parties. Civil right to vote is given to all Bermudians aged 18 years or older. Once the majority party emerges following a general election, a Premier is chosen from the majority party to head the cabinet with no more than 14 of the 36 members of legislature.
The upper house, called the Senate, comprises of 11 members; five of them are appointed by the Governor on advice of the Premier and three on the advice of the Opposition Leader. And the remaining three are appointed by the Governor on his own discretion. Senators serve under the directions of the Governor or the Premier.
There is also a lower house known as the House of Assembly, comprises of 40-members who are directly elected.
There are two main political parties in Bermuda - United Bermuda Party (UBP) and Progressive Labor Party (PLP). UBP had been in power right from the beginning until 1998 continuously for 30 years. Since 1998, PLP has come into power. An agenda of PLP has been to get a complete independence from Great Britain. However, they have not been able to pursue this actively due to various factors like the confidence of the International business community and so on.
Update June 2011:
As of June 30th 2011, the United Bermuda Party (UBP) has ceased to operate. This was the first party that came into power in Bermuda in 1968 when the constitution was introduced in the island. All the MPs except two had left the party to form the One Bermuda Alliance with the Bermuda Democratic Alliance. The last leader of UBP was Kim Swan.
Bermuda is a member of Caricom (with observer status), CCC, European Union (affiliate member through Great Britain), ICFTU, Interpol (as a sub-bureau) and the International Olympic Commission.
Due to its relationship with Great Britain, Bermuda is also part of all those organizations where Great Britain is, like the World Customs Union and the World Trade Organization.