NEW DELHI – The agreement at the NATO summit meeting in Lisbon on a transition plan to help end the war in Afghanistan within the next four years raises troubling questions about regional security and the global fight against transnational terrorism. As the US and other coalition partners gradually wind down their combat role, Afghan security forces – to number 300,000 after crash training of new recruits – are to take their place. But these local forces are unlikely to be able to hold the country together.