Which foundational change did the Emancipation Proclamation bring about?

The Emancipation Proclamation, issued by President Abraham Lincoln in 1863 during the Civil War, was a significant document that declared the freedom of all enslaved people in the states that were in rebellion against the Union. This proclamation fundamentally changed the legal status of enslaved individuals in those territories, transforming the nature of the war from a fight to preserve the Union into a struggle for freedom. The proclamation also allowed for the enlistment of African American soldiers in the Union Army, further emphasizing its importance in the fight against slavery.

The other options do not relate to the purpose or impact of the Emancipation Proclamation. The creation of a national park system and the establishment of a public school system are unrelated to the issues of slavery and emancipation, while granting women the right to vote became a prominent issue later in the early 20th century, well after the Emancipation Proclamation was issued. Thus, the correct answer highlights the crucial role the proclamation played in the movement towards abolishing slavery in the Confederate states.