Final answer:
Military strength was not a primary reason given in class for the United States' desire to become an empire; rather, acquiring raw materials and new markets were key motives for imperialism.
Step-by-step explanation:
The desire for the United States to become an empire in the past has been driven by several factors, but military strength is not one of the reasons given in the class material for this ambition. A primary aspect of imperialism in the nineteenth century was the acquisition of new territories for their raw materials and new markets to sell goods. This involved gaining control over parts of the world with low-cost resources and no competing mass-produced goods. Motives for imperialism included access to these raw materials, spreading cultural influence, and establishing military bases and infrastructure for strategic advantages, which Alfred Mahan particularly emphasized with his advocacy for a strong navy and a canal through Central America.