For the edification of millennial Marines: A "map" is defined as a paper representation of terrain that some say newly minted second lieutenants use to get their troops lost.

While Marines now have high-tech gadgets to help them figure out where they are, future adversaries can jam such devices, said Commandant Gen. Robert Neller.

"Think of all the stuff that we do that requires space-based, satellite-based communications: GPS, munitions, precision," Neller said. "If you were to lose that, what would that do to the way you thought you were going to fight?"

Members of Marine Wing Support Squadron 274's Engineer Company, Heavy Equipment Platoon review their map during a land navigation course at Marine Corps Air Station Cherry Point, N.C.

Photo Credit: Pfc. Nicholas P. Baird/Marine Corps

That means Marines will have to relearn how to use analog maps to prepare for fighting an enemy with cyber and electronic warfare capabilities, Neller said Thursday at the Atlantic Council think tank in Washington, D.C.

"We have a generation of Marines that have grown up assuming that the electromagnetic spectrum would be there for them; that they would turn on their gear and it would work 100 percent of the time, and it would be accurate," Neller said. "We're going to have to teach them that they're going to have to fight for that information. They're going to have to fight to get access to the spectrum."

Neller said the Marine Corps is watching how the Russians have fought in Ukraine and how the Chinese are training to get a sense of how future conflicts will be different from the wars in Iraq and Afghanistan.

The Russians have proven to be experts at jamming GPS, radar and communications equipment since they invaded Eastern Ukraine in 2014. The U.S. military has been eager to learn from the Ukrainians about how the Russians have integrated electronic warfare into their tactics, Army Lt. Gen. Ben Hodges, commander of the U.S. Army in Europe, told Marine Corps Times' sister publication Defense News.

"No Americans have been under Russian artillery or rocket fire or been on the receiving end of significant Russian electronic warfare, the jamming and collecting, for example, not tactical levels," Hodges said in the August interview.

Marines will have to practice using low-tech solutions for when their high-tech gear stops working in combat, Neller said.

"We have to unplug: All right, no more email," he said. "GPS doesn't work. Get out your map and your compass."

One challenge that Neller said he faces is making sure Marines younger than 25 care about maps again, Neller said. He recalled a visit he made to Afghanistan where en he asked a lieutenant to give a briefing using his map.

"He goes, 'Well, I don't have a map; I can show you on the Blue Force Tracker,'" Neller said. "I was terrified.

"I said: Yeah, but don't you have a map in your pocket – like a paper thing with laminate? Don't you have any grease pencils? He looked at me like: 'No.'"

Ultimately, the Marine Corps needs to increase the number of Marines dedicated to cyber and electronic warfare, even if that means taking Marines from operational units, Neller said. By summer, Neller expects to have an idea how many Marines are needed for those types of jobs, he said.

"You have one of two choices: You can ask for an end strength increase to grow the force in a different way; or you can take people that you have done one thing now and re-mission them to do something else — or a combination thereof," he said. "It takes 22 years to grow a colonel, so if we have to take structure, we'll probably take it from the more junior Marines because we can replace them — just because they're younger."

The United States Marine Corps in the Twenty-First Century

The United States Marine Corps in the Twenty-First Century