BRUSSELS – The pledge NATO member countries made to spend 2 percent of their gross domestic products on defense is largely symbolic and has served more to arrest the alliance-wide drop in military funding since the Cold War, according to a senior Pentagon official.

“The Wales pledge, in fact, has helped us stop the drop in defense spending,” the official said. “As small as that sounds, it is actually huge…It’s starting to tick up. It’s not every nation but most of the nations are doing that. The trend line is going up. How fast that will go up, I don’t know.”

A handful of U.S. Defense Department officials have spoken to the press on background at the ongoing NATO ministerial in Brussls, Belgium. They all spoke on the condition of anonymity. Secretary of Defense Ash Carter over two days is meeting with defense chiefs from several NATO countries to discuss Russian deterrence, the ongoing alliance mission in Afghanistan and to push for increased spending on collective defense.

“We’ve got to keep moving – the political will to spend the money, to make the changes, to do the adaptations to have strong deterrence,” the official said. “We have got to keep that going. This is just the beginning.”

As an alliance, NATO has decided its response to Russian sabre rattling is to send four battalions into the Baltic nations, but the alliance is still working through how those units should be equipped, according to a senior U.S. official with the alliance.

“There is a generic set of descriptive factors and elements,” said another U.S. defense higher-up. “A lot of the answer to the question is pre-decisional and the nations ultimately make those decisions and will inform the collective NATO body on their contribution.”

It is widely understood that Russia has positioned a robust set of weapons in and around Kaliningrad as a means to deter access to the Baltic Sea in a conflict. Officials also are concerned Russia could use an international incident as an excuse to unleash a Blitzkrieg against the Baltics, racing to capture the capitals of Latvia, Lithuania, Estonia and Poland while keeping U.S. and allied navies at bay with guided missiles.

NATO has committed four battalions, numbering about 4,000 troops, to the Baltics but has yet to decide what capabilities – short- and medium-range missile defense, armor, mobility – the units will carry with them.

“You have to look at the individual countries these battalions will be going into and what capabilities those countries already have and what they are going to be needing,” said a U.S. Army official assigned to Supreme Allied Powers Europe (SHAPE).

The U.S. military already plans to pour resources into the Continent under the European Reassurance Initiative (ERI), to which it set aside $3.4 billion for fiscal year 2017. It soon will have three brigades stationed in Europe on toe-to-toe rotations, the largest concentration of U.S. troops on the Continent since the Cold War.

The alliance, originally established as a collective deterrent to the Soviet Union, has focused its energy over the past 15 years on wars in the Middle East. It has now come full circle and must relearn how to perform its “classic” mission while continuing to offer a cooperative response to terrorism and other international challenges, another senior Pentagon official said. NATO’s transformation into a multi-mission alliance is not without growing pains, he said.

 “It cannot be overemphasized how really hard this is,” the official said. “The Cold War was a completely different time. We don’t need to be there. We can preserve ways to work with Russia. Nevertheless, the alliance has to adapt in order to put some teeth behind the dialogue with Moscow that goes up and down.”