To answer my own question it is roughly half of the Union army. But also remember who was making decisions about the war. In that sense, it was pretty much all white native born so regardless of who made up the fighting ranks, were they not fighting for what those white native born people wanted on not their own desires? I mean, that's the argument made for Confederate soldiers. So only fair, correct?
Lincoln made it clear, time and time again, that his objective in fighting the war was to preserve the Union. But he recognized that to win, an alliance with African Americans was needed, particularly with those African Americans in the South. Hence, we see the Emancipation Proclamation (EP), which was one of many steps that led to the emancipation of slaves and and the abolishment of slavery.
The EP was controversial. Democrats blasted it, many in the Border States hated it, and many people in the West disliked it.
In an August 1863 letter, Lincoln defended his policies of emancipation and black enlistment:
But to be plain, you are dissatisfied with me about the negro. Quite likely there is a difference of opinion between you and myself upon that subject. I certainly wish that all men could be free, while I suppose you do not. Yet I have neither adopted, nor proposed any measure, which is not consistent with even your view, provided you are for the Union. I suggested compensated emancipation; to which you replied you wished not to be taxed to buy negroes. But I had not asked you to be taxed to buy negroes, except in such way, as to save you from greater taxation to save the Union exclusively by other means.
You dislike the emancipation proclamation; and, perhaps, would have it retracted. You say it is unconstitutional--I think differently. I think the constitution invests its Commander-in-chief, with the law of war, in time of war. The most that can be said, if so much, is, that slaves are property. Is there--has there ever been--any question that by the law of war, property, both of enemies and friends, may be taken when needed? And is it not needed whenever taking it, helps us, or hurts the enemy? Armies, the world over, destroy enemies' property when they can not use it; and even destroy their own to keep it from the enemy. Civilized belligerents do all in their power to help themselves, or hurt the enemy, except a few things regarded as barbarous or cruel. Among the exceptions are the massacre of vanquished foes, and non-combatants, male and female.
You say you will not fight to free negroes. Some of them seem willing to fight for you; but, no matter. Fight you, then exclusively to save the Union. I issued the proclamation on purpose to aid you in saving the Union. Whenever you shall have conquered all resistence to the Union, if I shall urge you to continue fighting, it will be an apt time, then, for you to declare you will not fight to free negroes.
I thought that in your struggle for the Union, to whatever extent the negroes should cease helping the enemy, to that extent it weakened the enemy in his resistence to you. Do you think differently? I thought that whatever negroes can be got to do as soldiers, leaves just so much less for white soldiers to do, in saving the Union. Does it appear otherwise to you?
But negroes, like other people, act upon motives. Why should they do any thing for us, if we will do nothing for them? If they stake their lives for us, they must be prompted by the strongest motive--even the promise of freedom. And the promise being made, must be kept.
Lincoln's letter states unambiguously that his goal is to save the Union. But if the Union is to gain the support of negroes, it had to give them a "strong motive" to "stake their lives for us." "Why should they do any thing for us, if we will do nothing for them?", asks Lincoln.
Thus, Lincoln and the Union made ending slavery an objective of the war. Emancipation and abolition were clearly the means to an end, not ends in themselves, for white Union men. But for whites to achieve what they wanted, they had to achieve some things that the negroes wanted. This was a case where Union men and enslaved Confederate residents had a common goal - the end of the slaveholding Confederate nation.
- Alan