Both military historians and the United States military have long had an unhealthy fascination with the German Army of World War II. The Wehrmacht, the thinking goes, was both enormously effective (much more so than their enemies), and apolitical. Unstained by its lack of involvement in Nazi war crimes, the Wehrmacht was thus a useful military model. Add to that the start of the Cold War, in which the Soviets became the main enemy, and the American military looked to the Germans for information and inspiration. The apotheosis of this was Colonel Trevor Dupuy’s Quantified Judgment Model, which used a statistical analysis to conclude that Germans were more effective soldiers than Americans in World War II. The German’s Combat Effectiveness Value, according to Dupuy, was significantly higher than that of the Allies, western and eastern front alike. Each German soldier, Dupuy figured, was worth about 1.55 Americans.
The result of this fascination has come out in a number of ways, including the Marine Scout Snipers who decided that the SS symbol was a good one to adopt as their logo. But it also made the American Army focused on the kind of mechanized warfare that they took as the German model. Facing the Soviets across the Fulda Gap during World War II, American soldiers found themselves symbolically in the same position as the Germans in WWII (excepting the whole Germans invading the USSR thing, of course). That focus was (arguably) useful in Western Europe, but less so in other theaters, like Southeast Asia. The Germans were notoriously bad at counterinsurgency, and some of the American difficulties, I think, came over from the German model (note that pre-WWII, Americans had been pretty reasonable at counter-insurgency). The fascination with the Germans might also have influenced American imperial behavior; alone (I think) among major imperial powers, the United States did not have a separate imperial military force (like the Indian Army) that it used abroad.
The US military has gotten away from that obsession somewhat in recent years, and adapted quite well to the requirements of counterinsurgency (though it shows signs of backtracking in recent years), but, as the Marines demonstrated, the fascination with Nazi Germany remains.
 Military historians have pushed back against the apolitical image of the Wehrmacht in recent decades.
 Dupuy explained his model concisely here (subscription required, sorry). There were substantial problems with the analysis, outlined here and here. Dupuy recognized some of these problems, including a chapter called “Fudge Factors” in his book on the topic, Numbers, Predictions, and War.