WARSAW, Poland – For NATO, its two-day summit beginning Friday may be the most crucial since the Cold War. Alliance leaders will tackle an unprecedentedly complex set of challenges in search of ways to better guarantee their nations' security. Here are some key challenges, and what NATO heads of state and government are expected to do about each:
___
RESURGENT RUSSIA
Since its creation in 1949, NATO has seen its No. 1 responsibility as protecting its member states, which currently number 28, and their inhabitants, now nearly 1 billion.
The old Cold War foe, Russia, is back as a major alliance concern, as it rearms and conducts itself in what NATO deems unfriendly and provocative ways. The alliance accuses the Kremlin of backing a continuing armed insurgency in eastern Ukraine, and opposes the annexation of Crimea from Ukraine by Russia in 2014.
At Warsaw, building on decisions taken at NATO's last summit in September 2014, leaders will agree to beef up the alliance's presence in member countries that feel especially threatened by Russia. Four reinforced multinational battalions of an estimated 1,000 soldiers each will be deployed in Poland and the Baltic states of Estonia, Latvia and Lithuania.
To the south, a multinational brigade is planned for Romania as the beginning of NATO actions to reassure allies concerned about Russia's military buildup in the Black Sea.
At the same time, U.S. President Barack Obama and other leaders are expected to stress their desire for improved ties with Moscow, which NATO once regarded as a promising partner in efforts to build increased security in Europe and elsewhere. A post-summit meeting of the NATO-Russia Council, which groups envoys from NATO nations with their Russian counterpart, is scheduled for July 13 at alliance headquarters in Brussels.
___
EXTREMIST VIOLENCE
Many contemporary security worries for NATO countries don't come from other states, but from what specialists call "non-state actors" like the Islamic State group. Deadly suicide attacks claimed by the extremist Muslim group in Paris and Brussels were dramatic proof that existing law-enforcement and government measures were woefully inadequate to prevent such organizations from wreaking carnage in the West.
The Warsaw summit is expected to decide on stepped-up — though modest — NATO cooperation with the U.S.-led coalition fighting IS, including deployment of alliance AWACS surveillance aircraft and a program in Iraq to train the Iraqi military and improve the country's defense capabilities.
NATO leaders also will renew their commitment to Afghanistan by pledging to continue the alliance's Resolute Support mission to train and assist Afghan security forces and to keep contributing funds. The goal is to prevent Afghanistan, base of operations for Osama bin Laden and al-Qaida's Sept. 11, 2001, attacks on New York and Washington, D.C., from becoming a safe haven again for extremist Muslim groups operating abroad.
Leaders are also expected to consider a change in the alliance's maritime actions in the Central Mediterranean that ultimately could help stabilize Libya and cut migrant flows to Europe, concerns for some European NATO members.
___
INCREASED COOPERATION
NATO has increasingly come to see more joint action with the European Union economic bloc as key to coping with contemporary security threats, including from Russia and extremist Islamic groups.
In Warsaw, the two organizations will sign a formal agreement to pool efforts in specific areas, including fighting cyber threats, countering the blend of conventional military means and non-military techniques known as hybrid warfare, and increasing maritime security.
The presence of EU President Donald Tusk and the head of the EU's executive Commission, Jean-Claude Juncker, at NATO's biggest event in years will dramatize the two Brussels-based bureaucracies' resolve to work more closely together. NATO Secretary-General Jens Stoltenberg said the decision by British voters last month to leave the European Union only makes it more essential for the alliance and the EU to cooperate more.
Other meetings are planned in Warsaw with leaders or top officials of Ukraine, Georgia, Sweden, Finland and other key NATO partner countries. The Balkan nation of Montenegro, invited earlier this year to become NATO's 29th member, will also be present at the summit.
___
ADAPTING THE ALLIANCE
In recognition of the growing importance of the Internet and computers to a modern society's survival, NATO leaders will confirm cyberspace as an official "operational domain" for alliance actions, along with air, land and sea. They are also expected to sign a "cyber defense pledge" to strengthen their countries' networks.
The Warsaw summit will also order creation of a new Intelligence Division at NATO headquarters to organize and streamline handling of civilian and military intelligence among alliance members. The unit could lead to NATO's greater involvement in efforts to detect and foil extremist plots inside and outside alliance member countries.
Initial components of a high-tech network that NATO says is intended to serve as a protective umbrella against ballistic missiles launched by countries like Iran and North Korea will officially be declared operational during the summit. Russian officials, including President Vladimir Putin, say they suspect NATO's new capability is meant to act against their country's missile arsenal as well.