Jacob Zuma has been elected leader of South Africa's ruling ANC party at a stormy party conference. Unlike in New Zealand, Australia, Canada or the UK, Zuma doesn't automatically gain a executive post such as Prime Minister for being leader of the ruling party - instead, the incumbent President, Thabo Mbeki, retains his office until the next presidential election is held, which will be at the end of his term, as defined by the South African constitution, in 2009.

This may seem strange to us, but it's within the bounds of South Africa's Washminster system. Back in Walter Bagehot's time, it was easy to point out the differences between the Westminster and Washington systems. However, over the last 150 or so years the Westminster system in some constitutional monarchies has gradually come to be more of a "Washminster" - the chief executive officier, the Prime Minister, has gained the powers of a executive president, while maintaining the petticoat of monarchy. Ironically, other countries following the Westminster system, such as Ireland or Malta, now have a purer Westminster system than New Zealand or Australia because they have ceremonial Presidents with clearly defined powers, and the ability to use then, as Queen Victoria had during Bagehot's time.

One country to formally acknowledge the reality of its Washminster system is South Africa. From the success of a whites-only republic referendum in 1961, the South African Governor-General became the "State President", and retained all the powers of the former Viceroy. In 1983, at a time of increasing international pressure on the white minority apartheid government, a tri-cameral system for different races was established. As a result, the State President became an executive presidentcy, elected by the national assembly - in effect replacing the Prime Minister of South Africa. South Africa wasn't the first country to adopt such a system, its neighbour Botswana did so in 1965 when it gained independence from Britain. With South Africa's post-apartheid constitution in 1996, the office simply became "President".

The election of Zuma now means South Africa has moved further away from the Westminster system. With the Presidency and party leadership now in different hands, the situation is now more like that of the United States. As noted above, if Zuma won the leadership of the ruling party in Britain, he would automatically become Prime Minister, as John Major did in 1990.