Ukrainian troops are blind and deaf on the battlefield. Kiev’s members of parliament suddenly discover their cell phones don’t work. International observers watching the war lose contact with their drones and can’t do their job.

Welcome to Ukraine’s electronic war.

Throughout the conflict, the pro-Russian rebels in eastern Ukraine have disrupted Kiev’s communications. It’s a problem that Ukraine—lacking secure communications systems and jamming equipment of its own—can’t counter.

And as with other forms of overt and covert support provided to Ukraine’s separatists, all eyes are on Russia as the source of the interference. The rebels’ equipment is just too fancy.

“Russian electronic counter-measures, jamming, and cyber are all frequently deployed not only tactically against Ukrainian units in the field, but against larger strategic command and control systems right back to Kiev,” James Stavridis—NATO’s former Supreme Allied Commander in Europe and current dean of the Fletcher School—told War Is Boring in an email.

“Unquestionably these systems are all being operated directly by highly trained Russian troops.”

Stavridis coauthored a recent report for the Brookings Institution urging the U.S. to support Ukrainian forces with arms exports. He noted that the sophistication of electronic warfare systems are an indicator that Russian personnel—and not local separatists—are responsible for the jamming.

“The ‘insurgents’ lack the training, education, equipment, and general wherewithal to operate such systems—they are absolutely not ‘out of the box’ systems,” he wrote.

Russia is a pioneer of electronic warfare. In 1905, a Russian naval commander jammed the communications of a nearby Japanese ship using his radio during the Russo-Japanese war.

Moscow continues to lead the pack in electronic warfare, and witnesses in Ukraine have long reported seeing its jamming equipment in the country—everything from R-330Zh Zhitels to the new Tigr-M fitted with Leer-2 systems.

New York Times reporter C.J. Chivers snapped pictures of the vehicles during the invasion of Crimea. Pro-Ukrainian activists uploaded a video in March 2014 showing troops offloading both systems from a ferry across the Kerch Strait from Russia.

In November, the Organization for Security and Cooperation in Europe—an international conflict monitoring group—complained that the GPS systems on their drones had been jammed while flying over rebel-held territory in Mariupol.

In January, Ukrainian Facebook users reported seeing a Krasukha-4 electronic warfare system among rebel forces in Donetsk. The military grade jamming device can disrupt the communications of drones and aircraft.

To understand why these systems are so important, it’s helpful to understand how Ukraine and Russia fight. The two countries share a common military heritage and it influences the way both fight today.

“The U.S. and the West put primacy on the infantry, and the Soviets put the emphasis on artillery,” explained Charles Bartles—a Russia analyst at the Foreign Military Studies Office, part of the Army’s Training and Doctrine Command’s Intelligence Staff.

“They still require tanks and infantry to capture and hold ground, but the vast majority of damage is doctrinally planned to be done by the artillery,” Bartles said.

Artillery units placed beyond the line of sight of their targets are dependent on forward observers. Jamming their communications interferes with observers’ ability to relay target positions and adjust fire for greater accuracy.

Much of Ukraine’s armed forces and volunteer units use simple, commercial communications equipment for reconnaissance. That kind of equipment doesn’t stand a chance against the separatists’ sophisticated jamming tech.

“It’s very difficult for Ukrainian forces to operate on radios, telephones, and other non-secure means of communications because their opponents haveexceptional jamming capabilities,” Lt. Gen. Ben Hodges, commander of U.S. Army Forces in Europe, told reporters in January.

Ukraine had been home to companies producing some electronic warfare equipment, including the Topaz company in Donetsk. But reports from the city indicate that Russian aid convoys looted much of the machinery at the plant for transport back to Russia.

Last summer, VK users said that Russian-backed separatists stole a number of Topaz MANDAT-B1E jamming stations, and backed up the claim with photographs of a convoy in Donetsk.

Stavridis argued that the United States should provide the Ukrainians with electronic counter-measures, so they can disrupt separatists’ use of Russian-provided UAVs, which have helped the rebels direct punishing artillery fire.

But Ukraine is relatively calm at the moment. Another ceasefire accord has calmed the fighting, and Obama administration officials are reportedly on the fence about sending arms to Ukrainian forces. That’s despite calls from Congress to arm Kiev’s troops.

Still, ceasefires in Ukraine are fragile. If the peace doesn’t last, the airwaves over Ukraine will once again be a battlefield.