Leaders from the North Atlantic Treaty Organization will meet in Lisbon, Portugal Friday to discuss a new post-Cold War era mission, the war in Afghanistan, and their relationship with Russia.
NATO is expected to unveil a new "strategic concept" to address global security concerns that have drastically shifted since the alliance last revised its mission 11 years ago.
The new focus of the 28-member Western military alliance was drafted by a group of experts led by former U.S. Secretary of State Madeleine Albright.
A former U.S. ambassador to NATO, Robert Hunter, says the evolution of security challenges over the last decade from territorial disputes to global terrorism, cross-border crime and cyber threats has shaped the new focus of the organization.
Afghanistan also will top the agenda of the two-day summit.
U.S. President Barack Obama is expected to outline a four-year withdrawal plan of 130,000 NATO troops, which is set to begin next year and will gradually hand over control to Afghan security forces.
Leaders also are likely to review the alliance's three-fold mission in Afghanistan, which entails helping the Afghan government rebuild and stabilize the country, train Afghan security forces and eliminate Taliban strongholds.
Afghan President Hamid Karzai, who has repeatedly criticized aspects of NATO's mission tactics in Afghanistan, is expected to attend the summit.
Former Cold War rival Russia has been invited to the summit in an effort to deepen Moscow's cooperation with the military alliance on an array of issues, including a new missile defense system and the Afghan war.
NATO leaders also will discuss building new partnerships with South Korea and Japan.
Secretary-General Anders Fogh Rasmussen calls the summit one of the most important in NATO's history. He said the key outcome of the NATO summit will be a "more effective, engaged and efficient" alliance.