Actually, I think we're both right. From 1789 until the Civil War, we were still a "grouping" (by whatever name applies) of sovereign states, operating under the Constitution. The Civil War destroyed that point of view (illegally, in my view). On the moral question of slavery, the South was wrong. On the political question of secession and state sovereignty, the South was right.
As soon as the Constitution was ratified, the states were no longer sovereign. It took a while for it to become obvious, and for all the various supreme court cases interpreting the constitution to pile up, but it was a fait accompli. The Constitution killed state sovereignty.
So they weren't deeply involved in questions of liberty and good government. Far from it. They were simply a regional interest run amok. They added to the list of things about which James Madison was wrong. He had predicted that the new government would stifle factional rivalries. That was one of the reasons we supposedly needed a new constitution: the confederacy was at risk of intrastate war, they warned. And yet the national government created by the framers led us directly into civil war.
I'd have some respect for the slavers if they had put any thought into a real constitution. They even say "we the people" not "we the states" as the old articles of confederation did. It's absurd.
The old articles are pretty cool. There was no supreme court. Cases were settled by the United States in Congress.