The Beltway rumour mill was right, Colin Powell today announced his endorsement of the Democrat presidential nominee Barack Obama.

As a former Army General and Secretary of State in the Bush administration, Powell’s support will be seen as important in bolstering Obama’s foreign policy proposals, which include a “phased withdrawal” from Iraq.

Powell used the endorsement, made on NBC’s Meet the Press, to stress his long friendship with Obama’s rival, John McCain, but added that his vice-presidential hopeful Sarah Palin, isn’t ready to be President of the United States.

UPDATE [Aaron]: I’ve just listened to the audio from the Meet the Press interview, and Powell stressed the GOP’s lurch to the right as an important factor in his decision. Powell’s ‘defection’ may prove to be decisive in cementing the support of centre-right Republicans – the much-discussed ‘Obamacans’ – who feel alienated by the appointment of Palin and McCain’s reliance on divisive political tactics.

Powell rejected the culture-war that McCain has embraced.

Commentators also mentioned the importance of Powell as a retired veteran, with regard to the ageing populations of Florida. Many former members of the military live in the crucial state of Florida and would be considered natural McCain voters.