CHICAGO - In addition to pledging an "irreversible transition" in Afghanistan, NATO's 28 partner nations agreed at their Chicago summit on steps to ensure the alliance's viability, and its ability to respond effectively to future threats and challenges in tight economic times.
NATO leaders came to Chicago with the objectives of improving the efficiency of NATO operations, increasing burden-sharing and positioning the alliance as a reliable global security hub.
A final declaration commits to a "leaner, more effective and affordable" NATO command structure,including steps to make better use of the budgets of member countries.
What is called "NATO Forces 2020" involves "modern, tightly connected forces, able to "operate together and with partners in any environment."
NATO said "complex security challenges and financial difficulties" make it more important than ever to make the best use of resources while remaining committed to key principles, including collective defense.
Demonstrators flow out of Grant Park in Chicago during this weekend's NATO summit Sunday, May 20, 2012 in Chicago.
U.S. President Barack Obama during a meeting with Afghanistan's President Hamid Karzai at the NATO Summit at McCormick Place in Chicago, May 20, 2012.
Leaders watch a ceremony honoring NATO military personnel for their service the NATO Summit meeting in Chicago, May 20, 2012.
NATO Secretary-General Anders Fogh Rasmussen arrives at the NATO Summit in Chicago, May 21, 2012.
A demonstrator sits in a tree Grant Park before a march in Chicago, May 20, 2012.
A Chicago Police officer confronts a protester during a march and rally at this weekend's NATO summit.
German Chancellor Angela Merkel talks to President Obama at the Summit. At left is NATO Secretary General Anders Fogh Rasmussen.
Leaders pose for a family photo outside Soldier Field, May 20, 2012.
President Barack Obama and British Prime Minister David Cameron help Secretary General Anders Fogh Rasmussen find his toe marker.
Valerie Trierweiler, partner of Francois Hollande, and first lady Michelle Obama watch a student explain the making of a meal during a tour of the Gary Corner Youth Center in Chicago.
A protester covered in silver paint purchases a rail ticket following an anti-NATO protest march in Chicago, May 20, 2012.
Secretary General Anders Fogh Rasmussen discussed the importance of these principles at a meeting of NATO's Atlantic Council.
"Together we will keep NATO capable of responding to the security challenges of tomorrow, because no country and no continent can deal with them alone," said Rasmussen. "We must embrace a renewed culture of cooperation to provide more security at lesser cost for all of our citizens."
Prominent in the declaration is last year's military operation in Libya, which NATO said showed the allies' ability to "quickly and effectively conduct complex operations." But NATO said it also left important lessons to be incorporated into plans and policies.
President Barack Obama said though times have changed, the fundamental reason for NATO's existence, ensuring "common security, freedom and prosperity" remains unchanged.
"In good times and in bad our alliance has endured. In fact, it has thrived, because we share an unbreakable commitment to the freedom and security of our citizens," said Obama. "We have seen this from the Cold War, to the Balkans, to Afghanistan and Libya."
NATO also cites operations in Kosovo, counter-piracy operations in the Indian Ocean and logistical support for the African Union in Somalia, and the concluded NATO training mission in Iraq.
Significant outcomes include a Defense Posture Review that reaffirms "an appropriate mix of nuclear, conventional and missile defense capabilities," and an Alliance Ground Surveillance System involving drone aircraft for intelligence gathering.
NATO declared an "interim" capability for ballistic missile defense, involving the U.S.-funded system to protect against potential launches from Iran and other countries such as North Korea. Leaders will continue efforts to resolve differences with Russia over the system.
NATO also focused attention on the importance of its ties with partner nations, and its support for countries seeking membership, including Bosnia-Herzegovina, Macedonia, Montenegro and Georgia.
Secretary of State Hillary Clinton reaffirmed NATO's "open-door policy," saying the alliance looks forward to the day when these countries implement all necessary reforms for membership in an expanded alliance. "Here in Chicago let us reaffirm our commitment to enlargement, done right, as a core element of our purpose and our community," she said.
On Syria, leaders said only that they continue to "follow the evolution of the Syrian crisis with growing concern," and strongly support full implementation of the United Nations-backed Annan plan to find a peaceful solution.
NATO urged Iran to build the confidence of the international community on the peaceful nature of its nuclear program, and supports a diplomatic solution under the P5+1 negotiations with Tehran.
NATO urged North Korea to fully comply with its international obligations and abandon all activities related to its existing nuclear weapons and ballistic missile programs in a complete, verifiable and irreversible manner.