President Obama and other NATO leaders are gathering in the Portuguesa capital Lisbon for talks what is being billed as one of the most crucial summits in the alliance's 61-year history.The meeting has been described as one of the most important summits in NATO's history as it seeks to update a strategy and structure to face new security threats. One import part of the plans is an effort to reach agreement on a Nato wide missile defence system operated from US ships in the Mediterranean. NATO leaders want to cooperate on the plans with Russia which strongly opposed previous plans for a land-based missile defence shield. Tomorrow the discussions will focus on Afghanistan with efforts to agree a framework for the hand over of responsibility for security to the Afghan government by 2014.