Increasing NATO’s speed has become Lieutenant General Ben Hodges’ mantra.

Every time that Russia holds snap exercises moving tens of thousands of men across vast distances, the United States is surprised, the commander of the U.S. Army in Europe said in an interview last week. By contrast, the 28 countries of the North Atlantic Treaty Organization are so tied up in red tape that it typically takes 15 days to get diplomatic clearance to move military equipment from one member state to the next. Cold War-era regulations mean Hodges still needs special permission to travel from his base in western Germany to Berlin.

“What we want is like a military Schengen zone,” the three-star U.S. general said, referring to the border-free travel regime adopted by most European Union countries. “Right now refugees can move across Europe faster than military convoys.”

While Europeans have become riveted on the terrorist menace of Islamic State following the Paris attacks, Hodges remains just as focused on new threats posed by Russia. Even as the Kremlin reaches out to cooperate militarily in Syria, he warns, the Russian intervention in Ukraine exposed vulnerabilities in NATO that urgently need to be remedied.

“When you look at the weapons systems that they have put into Crimea, they can range about 90 percent of the Black Sea,” Hodges said. “If they wanted to, they could affect what goes in and out.” Three NATO allies — Turkey, Bulgaria, and Romania — border the Black Sea.

At the same time, Russia has the ability to block the Baltic Sea using forces based in the Russian enclave of Kaliningrad, according to Hodges. After the lightning occupation of Crimea in March 2014, Western military planners started considering the possibility of Russian shock troops sealing the 50-mile border between Poland and Lithuania, creating a land bridge from Kaliningrad to Russian ally Belarus and cutting off the three Baltic states from their NATO allies.

Hodges talks about the “Suwalki Gap,” named after the Polish town on the Lithuanian border, in the same way that U.S. strategists used to refer to the Fulda Gap, once one of the most likely paths for a Soviet attack on West Germany. Is it likely that Russia would try to close the Suwalki Gap? “No,” said Hodges. “But I didn’t think Crimea was likely either. Nobody expected that.”

Speed of assembly is just one aspect of the needed change. NATO also needs to increase the speed with which it recognizes what’s happening on the ground to give political leaders more time to make decisions, Hodges said. Russia’s hybrid tactics in Ukraine created so much confusion in Western capitals that the Kremlin could present the annexation of Crimea as a fait accompli. NATO’s nightmare scenario is a Russian move on the Baltics to test the alliance’s resolve in defending its most vulnerable members.

To disabuse the Kremlin of any temptation, the Obama administration has dug up deterrence as the cornerstone of its European strategy. Defense Secretary Ash Carter announced in June that the United States would pre-position heavy equipment, including 250 tanks, in Eastern Europe.

“Deterrence is not always a popular word. For some it contains echoes of the Cold War,” Alexander Vershbow, NATO’s deputy secretary-general and a former U.S. ambassador to Russia, said during a visit to Berlin last week. “Being strong enough to prevent others from attacking you is not an act of aggression.”

The U.S. build-up is a reversal after more than two decades of gradual withdrawal. Hodges commands 29,000 U.S. troops, down from 213,000 who were based in Europe in 1989, the year the Berlin Wall came down. The last U.S. Army tank left Germany less than a year before Russia seized Crimea.

Although the Kremlin officially denies any military involvement in eastern Ukraine, NATO planners are keen to learn from the reality on the ground, where Ukrainian soldiers have been exposed to the latest in Russian tactics and weaponry.

“There’s an opportunity for us to learn and increase our understanding of the full sweep of Russian unmanned aerial systems, the type of munitions they’re firing, how their equipment performs,” Hodges said. “We’ve formalized that process to share it not just inside the United States but across the alliance.”

At the same time, the U.S. 173rd Airborne Brigade is leading a training program for Ukrainian forces that will continue through 2016, Hodges said. Earlier this month, the United States delivered mobile radar stations to help the Ukrainian military locate enemy artillery.

While many European governments are hoping for a shaky ceasefire to hold in eastern Ukraine and a normalization in relations with Russia, the Obama administration is taking no chances. The United States has been wary of calls by France to unite with Russia in defeating Islamic State.

“I think it’s important that the world doesn’t separate what the Russians are doing in Syria with the rest of their behavior,” Hodges said. “It’s not impossible to work with them in some areas while we have difference in other areas. That’s as old as nations.”

Besides seeking to maintain its foothold in the Middle East and present itself as a global power, Hodges said, Russia declared war on Islamic State to distract attention from Ukraine.

He refused to be called on whether Islamic State hadn’t surpassed Russia as the main threat to European security. While Russia has the capability to destroy the United States and its allies with its nuclear arsenal, it hasn’t expressed intent, Hodges said. Conversely, while Islamic State doesn’t come close to Russia’s destructive potential, it has made its intentions clear.

“To say which one’s the number one — to me it’s different categories of prioritization,” Hodges said. “You have to deal with each.”

As a symbol of the United States’ commitment to the pro-Western government in Kiev, Hodges carries a blue and yellow ribbon on his black backpack. An old woman gave him the miniature Ukrainian banner during joint military exercises in Ukraine last year.