The green troops of the 99th, along with the battle-tested 2nd Infantry Division, held a key sector controlling access to Spa and Liege and large repositories of ammunition, fuel, and supplies.

[4][5] He attended Cornell University, and left in his junior year to enlist in the United States Army for World War I.

[4] He then served as G-3 and executive officer (XO) of the 4th Brigade, part of the 2nd Infantry Division stationed at Fort Francis E. Warren, Wyoming, from 1930 to 1935.

Lauer attended the U.S. Army Command and General Staff College at Fort Leavenworth, Kansas, graduating on 20 June 1938.

[4] On 24 December 1941, less than three weeks after the United States entered World War II, he was promoted to the temporary rank of colonel[10] and appointed chief of staff of the 3rd Infantry Division, a Regular Army formation, and he took part in planning and leading the 3rd Division's amphibious warfare training and worked out special equipment and special operating procedures for amphibious operations.

He landed with the division at Fedala during Operation Brushwood on 8 November 1942, and helped capture Casablanca in the opening stages of the Allied invasion of North Africa.

[4] The green 99th ID faced a German force that during the Battle of the Bulge on the northern shoulder at Elsenborn Ridge was judged to be 5 to 15 times greater in size.

The determined effort and short time in front line combat led to UP correspondent John McDermott nicknaming the 99th as the "Battle Babies."

[11] Lauer retired from military service on 31 March 1946, but worked in Europe for the United Nations Relief and Rehabilitation Administration until early 1947.

[12] He returned to the United States and moved to Monterey, California, near Fort Ord, the successor to Gigling Reservation, which he helped found and build in 1941 and 1942.