A perhaps interesting bit from the musical "1776," which is obviously not a source for accurate history, but which nonetheless crystallizes why abolitionists iamong the founding fathers might have had to accept a non-ideal outcome on that issue:
Dr. Benjamin Franklin: We've no choice, John. The slavery clause has got to go.
John Adams: [stunned] Franklin, what are you saying?
Dr. Benjamin Franklin: It's a luxury we can't afford.
John Adams: [pause, then] 'Luxury?' A half million souls in chains... and Dr. Franklin calls it a 'luxury!' Maybe you should have walked out with the South!
Dr. Benjamin Franklin: [dangerous] You forget yourself sir. I founded the FIRST anti-slavery society on this continent.
John Adams: Oh, don't wave your credentials at me! Maybe it's time you had them renewed!
Dr. Benjamin Franklin: [angrily] The issue here is independence! Maybe you have forgotten that fact, but I have not! How DARE you jeopardize our cause, when we've come so far? These men, no matter how much we may disagree with them, are not ribbon clerks to be ordered about - they are proud, accomplished men, the cream of their colonies. And whether you like them or not, they and the people they represent will be part of this new nation that YOU hope to create. Now, either learn how to live with them, or pack up and go home!
Slightly later, Franklin is made to say:
Dr. Benjamin Franklin: Besides, what would posterity think we were? Demi-gods? We're men, no more no less, trying to get a nation started against greater odds than a more generous God would have allowed. First things first, John. Independence; America. If we don't secure that, what difference will the rest make?