Slavery as a Foundation of America?

A question we seem to ask often today is how slavery could have been tolerated in American society. It seems like such a contradiction to ‘American’ and ‘Christian’ ideals. I feel slavery was justified in the mind of wealthy colonists through the profit it produced. This speaks to the corruptibility of man, and how morals get lost in the foundation industry. After which this loss of morality can be used, naively, as a source of cultural identity
In select cases however, the use of slavery might have been out of the need to found a new nation. In some sense it was in the interest of America as a nation to own slaves, as the use of slave labor became entwined with colonial economics. Jefferson for example, used slave labor to gain economic and intellectual status. Status that proved invaluable to Jefferson’s role as a founding father.
They question I’d like to ask instead is: Would the colonies have had the strength to form themselves into a nation without the use of slave labor. And if not, at what level is it acceptable to allow enslavement in the aid of a ‘just’ cause?