In what some are terming NATO's most important meeting in a generation, U.S. President Barack Obama and the leaders of the 27 other member nations are deciding how to retool the Cold War-era military alliance to face a daunting range of modern threats, from a hostile Kremlin to religious-fueled violence and attacks in cyberspace.
They meet in the Polish capital, Warsaw, for a two-day summit starting Friday.
"We live in a more dangerous world, with terrorism, with turmoil, especially to the south of the alliance, in Iraq, Syria, North Africa," NATO Secretary-General Jens Stoltenberg told The Associated Press. "But also with a Russia which is more assertive, a Russia which has tripled its defense spending since 2000, and which has used force against an independent nation in Europe, Ukraine."
"This has really changed our security environment," Stoltenberg said. "NATO has to respond. When the world is changing, we have to change."
Recently, yet another factor of uncertainty has arisen inside the trans-Atlantic community with the decision by British voters to pull their country — NATO's leading European military power — out of the European Union, just as the economic bloc and the U.S-led alliance are planning unprecedented cooperation on security and defense.
The British electorate's June 23 choice "really puts into question the confidence of the West," Michal Baranowski, director of the Warsaw office of the German Marshall Fund think tank, said this week. "The silver lining could be that the Brits decide to double down on NATO, and be super helpful in NATO since they won't be in the EU."
Heads of state and government assembled in Warsaw will give the formal go-ahead to the greatest reinforcement of collective alliance defense since the collapse of the Soviet Union, including deployment of four reinforced multinational battalions, headed by the U.S., Britain, Canada and Germany, to Poland and the Baltic states.
The new units, totaling roughly 4,000 troops, will serve as a reassurance to allies feeling threatened by Moscow that NATO has their back, and also as a warning to Russia that a military incursion into the territory of front-line NATO states could bring it into head-to-head confrontation with the whole alliance.
"NATO is based on the core idea of one for all, and all for one," said Stoltenberg.
Further to the south, a Romanian-led multinational brigade is also planned as the start of an increased NATO presence designed to reassure and protect allies concerned about Moscow's beefed-up military presence in the Black Sea.
The measures to be ordered in Warsaw, which complement national actions by the U.S. and some other allies, constitute "the most significant accomplishment of alliance deterrence and defense in decades," Polish NATO Ambassador Jacek Najder told a pre-summit media briefing in Brussels.
Russian officials have already vowed to take unspecified but appropriate countermeasures.
"The Soviet Union is no more; the Warsaw Pact has ceased to exist," Russian President Vladimir Putin said recently, referring to the now-defunct military alliance between Moscow and its Eastern European satellites that was also formalized in Poland's capital. "But for some reason, NATO continues to expand its infrastructure and advance toward Russia's borders."
One independent Washington-based analyst, however, termed NATO's actions "too little, too late," and predicted they will be largely ineffective against Moscow's military, which has an official strength of 1 million.
"It's a minimal effort, with incremental steps," Jorge Benitez, senior fellow at the Brent Scowcroft Center on International Security, told the AP. "The little we do is quickly superseded by what the Russians do."
A second major set of decisions expected at the Warsaw summit concern what NATO officials call projecting stability beyond the alliance's borders. Here a priority concern is the Islamic State group, which has exploited the territory it holds in Syria and Iraq to mount devastating suicide attacks in the NATO member capitals of Paris and Brussels.
The extremist Muslim organization is also suspected of last week's attack by three suicide bombers that killed 44 people at Istanbul's airport.
At Warsaw, NATO leaders are expected to agree "on how we can do more also in the fight against terrorism, including strengthening our sharing of intelligence," Stoltenberg said.
Alliance AWACS surveillance aircraft will likely be ordered to peer into Islamic State-controlled areas of Syria and Iraq to assist the U.S.-led coalition combating the group, probably beginning this fall.
Leaders are also expected to order NATO training and capacity-building operations inside Iraq for that nation's military, and to pledge to renew their funding and training commitments to Afghanistan's government and security forces, which are increasingly hard-pressed by Taliban insurgents.
NATO and EU officials will also sign a pledge to boost cooperation against an array of security threats, including cyberattacks and organized disinformation campaigns. NATO leaders are also expected to order creation of a new Intelligence Division at alliance headquarters to streamline the collection and sharing of civilian and military intelligence and enable NATO to be more effective in combating extremist threats against allied member nations and their populations.
"We need NATO to continue to adapt in order to be able to react to the continued erosion of Europe's security," said Adam Thomson, British ambassador to the alliance.