Robert E. Lee's father & uncle, were very much a part of that commitment. Daniel Webster certainly understood it, in supporting the compromise of 1850 (see Daniel Webster Address).
Sadly, the compromise, so eloquently supported by Webster, did not stop the endless sniping against the honorable intentions of the Southern partners. It is not the subjects of that sniping that are as important as the breach of the essential mutual respect, which made the American compact possible.
"Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security"they should have added, "or if your feelings are hurt because someone said it's not good for you to own slaves, then it's totally okay, too."