The new federal holiday of Juneteenth should remind us that slavery ended in America because of forty years of struggle and sacrifice by whites and blacks alike.
Whites in the north fought to keep slavery out of new western territories, and to help thousands of blacks escape for years before the Civil War.  That crippled the slave economy in many southern states.
Abraham Lincoln helped form the Republican Party to end slavery long before he became President and signed the Emancipation Proclamation.
Three hundred ten thousand white and forty thousand black Union soldiers fought and died to end slavery in the South.
Most of them died in battles like Gettysburg, Spotsylvania, and the Wilderness after the Emancipation Proclamation.  That is why it so long for slaves in Texas to be free.