Why did the U. S get involved in World War I?

Declared war on 6 April 1917.

Explanation:

Currently, right before the United States declared war on 6 April 1917, the United States had sought unsuccessfully to remain neutral but related to Britain, deception, the destruction of German warships, and a German effort to have Mexico wage war on the United States forced the United States to intervene.

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roosevelt believed that in light of the country's recent military successes, it was unnecessary to use force to achieve foreign policy goals, so long as the military could threaten force. this belief, and his strategy of “speaking softly and carrying a big stick,” shaped much of roosevelt's foreign policy.