how did the emancipation proclamation change the nature of the war for former slaves and african americans?

Explanation:

On September 22, 1862, he released the preliminary Emancipation Proclamation, which served as a warning to the states in rebellion: if they did not rejoin the Union by January 1, 1863, their slaves would be freed. ... The war was no longer just about preserving the Union— it was also about freeing the slaves.

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