You must remember that the States freely associated with each other to form the united States (little u). The Constitution is the framework by which the division of powers was formulated between the Federal government, State governments, and the people. If the Constitution did not specifically enumerate a power of the Federal government, IT DID NOT HAVE THAT POWER!
The States were sovereign and independant entities, and were free to legislate and regulate to theirs hearts content, as long as they did not usurp powers that they agreed would be the province of the Federal Government or of the people.
The Federal government took on a national character when dealing with forces external to the states, ie - diplomacy and war. The federal character was invoked in internal dealing, with powers strictly limited by the Constitution.
The people were citizens of their State first and the united States second. For internal matters, State citizenship was paramount, and National citizenship took hold in external dealing, same as with the Federal government.
Each State is supposed to be free to chart it's own destiny, adhere to it's own beliefs, and formulate the character of the State, regardless of what the other States feel or do, and regardless of what the other States think of what they are doing. If a citizen of the State does not like living in the society and adhereing to the laws of his State, he can vote with his feet and move to another State. If enough people don't like the Status Quo they can vote the bastards out of office and make the desired changes through their newly elected representative.
There is no restriction in the Constitution to keep the States from seceeding from the uniited States. More specifically, there is no power enumerated in the Constitution to empower the Federal government to stop a State from seceeding.
The Federal government, dominated by Nothern States power block, had been levying increasingly excessive protectionist tariffs and duties for at least 50 years before 1861. The tariffs and duties were enacted in an effort to build up the industrial infrastructure of the Northern States, and most of the tariff and duties were paid by the agricultural Southern States.
After decades of attempting to alleviate the financial drain placed on the Southern economies by the Federal tariffs and duties, the South decided in 1861 to vote with their feet, and leave the Union.
After secession the Federal government initially did nothing to nullify the secession and "preserve" the Union. President Buchanan refused to send troops to put down the "insurrection" because he could find no Constitutional authority that would permit him to do so legally. Abraham Lincoln ignored the Federal government's enumerated powers and precipitated the War of Northern Agression to placate the Northern States, who were themselves threatening to seceed from the Union so they could establish free trade ports that could compete with the new Southern free trade ports.
The long term end results of the War of Northern Agression was to futher erode and eliminate the rights of the individual States to determine the character and nature of their own society. This has continued to this day as the power of the States continues to be usurped with every new unconstitutional law passed by the Federal government. What does that mean to you?