Like it or not, that was how the original Constitution was written, and enforced. An Oath to God was required, and Human law was not to encroach upon God's law. What was Caesar's, was Caesar's, and what was God's, was God's.

The South had absolutely no initial problem with changing the 'Constitution' unilaterally. A new Federal union, a new Constitution. I am talking about the complete collapse of the existing Union and building a complete new one from scratch, not a constitutional convention. Like GM going bankrupt, and then restructuring, nothing about the governance carries over except the name and the physical plant. A complete change in ownership and governance.

Incidentally, that is how South Asia is turning America into a branch plant operation - they are buying up the asserts (including the name and branding) of the large (and small) American corporations, and restructuring them into Asian controlled corporations. Trump is just accelerating the process. An American corporation that manufactures all (or most) of their product in Asia and imports it, goes under because they can not bring their own product in from Asia cheaply, so they go bankrupt and Asia buys the assets. That's why China will not bother to negotiate trade with Trump. They now realize his tariffs are exactly what their long range plans need. The longer they go on for, the cheaper it will be for them to 'Buy America'. The GE Appliance Division, for example. Bought by Haier, product made in America, profits go back to China.