Gen. Dwight D. Eisenhower had a problem. In June 1944, Allied forces had landed on Normandy Beach in France and were moving east toward Nazi Germany at a clip of sometimes 75 miles (121 kilometers) per day.

With most of the French rail system in ruins, the Allies had to find a way to transport supplies to the advancing soldiers.

“Our spearheads … were moving swiftly,” Eisenhower later recalled. “The supply service had to catch these with loaded trucks. Every mile doubled the difficulty because the supply truck had always to make a two-way run to the beaches and back, in order to deliver another load to the marching troops.”

The solution to this logistics problem was the creation of the Red Ball Express, a massive fleet of nearly 6,000 2½-ton General Motors cargo trucks. The term Red Ball came from a railway tradition whereby railmen marked priority cars with a red dot.

From August through November 1944, 23,000 American truck drivers and cargo loaders – 70% of whom were Black – moved more than 400,000 tons of ammunition, gasoline, medical supplies and rations to battlefronts in France, Belgium and Germany.

These Red Ball Express trucks and the Black men who drove and loaded them made the U.S. Army the most mobile and mechanized force in the war.

They also demonstrated what military planners have long understood – logistics shape what is possible on the fields of battle.

That’s a point well known in today’s war in Ukraine: As the Russian invasion stretches into its second month, logistics have been an important factor.