In 2003 Nato took its operations outside Europe for the first time when it assumed strategic command of the UN-mandated peacekeeping force in and immediately around the Afghan capital, Kabul.

BBC: Profile: Nato

One Western naval officer says placing all the warships under a single command, perhaps of the UN, and adopting the same rules of engagement would help to make them more effective.

ECONOMIST: Piracy off Somalia

The UN has accused Rwanda and Uganda of backing the M23, saying the chain of command culminates with Rwandan Defence Minister James Kabarebe.

BBC: DR Congo crisis: M23 rebel leader 'flies to Uganda'

After meeting America's secretary of state, Colin Powell, on Thursday, and Britain's foreign secretary, Jack Straw, on Friday, Mr Annan acknowledged that diplomats were discussing the possibility of agreeing a multinational force to guard UN sites and staff, with a separate command structure but in some way under the influence of the American military.

ECONOMIST: Iraq's security void

If man-made greenhouse gas emissions are approaching a critical threshold, as the UN's climate experts suggest, the time spent on projects that abate relatively rare gases, but command artificially large profits, may prove a costly distraction.

ECONOMIST: The treaties that pay you to pollute

These troops come as formed units and are very largely under their own national command day-to-day, even though there are standards of behavior laid down by the UN.

BBC: What You've Said

The UN calculates a population's human capital based on its average years of schooling, the wage its workers can command and the number of years they can expect to work before they retire (or die).

ECONOMIST: A new report comes up with a better way to size up wealth