Final answer:
All factors mentioned fueled the new American imperialism except the need for new workers for factories.
Step-by-step explanation:
All of the factors mentioned - desire for military strength, need for new workers, and thirst for new markets - actually fueled the new American imperialism. However, if we have to select an option that did not contribute to it, it would be the 'Need for new workers for their new factories'. The primary driving forces behind American imperialism were the desire to secure military strengths, expand influence, and gain access to new markets and resources.
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