How did the emancipation proclamation support the union’s military cause?

It proclaimed the freedom of slaves in the ten confederate states and it also decreed that freed slaves could be enlisted in the Union Army.

Explanation:

Emancipation Proclamation completely changed the meaning and purpose of civil war. The Emancipation Proclamation was an executive order issued by Abraham Lincoln on January 1, 1863.

In the next 2 and half years around 180,000 of them fought in the Union army and 10,000 in the navy, making a vital contribution to Union victory as well as their own freedom.

“i think it is very plausible that if there are five votes to end the death penalty, it could be with the people who are on the court right now,” - smith

so basically it is not clearly and consistently imposed