Whenever people are upset with federal actions, they point to their state flag and say they shouldn't have to comply with that federal statute because their state has a right to ignore it.
These people are not just wrong, they're wrong by more than 150 years.
Before 1860, Congress consisted of a united nations of autonomous states. Each of those states had their own laws, their own governments, their own economies. Their banks issued their own money and the title "governor" was equivalent to the later title "president." They considered themselves separate entities from each other, a holdover from the colonial times when each was a separate colony.
That's why the so-called "Civil War" should be more accurately called the War Between the States. "Civil war" infers that there was a unified nation previous to its outbreak. That simply is not true. There were 33 independent and separate nations, working sometimes together and sometimes at odds.
The abolition movement, which had been gaining strength in the northern nations since the American Revolution, eventually overwhelmed the southern nations' interests and forced a conflict between the states. The southern nations depended almost exclusively on slave labor for their economic well-being. Forcing them to free their slaves would destroy the economy and plunge their populace into poverty and despair. There was no alternative to slavery at the time for most of the larger farmers. To replace the slaves with horses and oxen would bankrupt them. Little wonder they pressured their governments to secede from Congress. For them, it was simply a matter of economic survival.
The southern states became a separate nation, the Confederated States of America. That new nation was not beaten. Make no mistake, it was conquered. The conquered nation's citizens were even required to swear a loyalty oath to the USA before they would be pardoned, just as if they were aliens immigrating into the country from outside its borders.
Even though previous US presidents had argued that the states constituted a unified nation, this was never accepted in the south. Not until Texas vs. White in 1869 was it undeniably established by SCOTUS that this issue was completely settled.
The United States became a single, homogeneous union by SCOTUS edict.
Federal law became the law of the land from one coast to another. State laws were allowed except where they conflicted with federal statute. No longer did the states have the right to autonomy. The United States of America is a misnomer. The nation should be renamed the Federation of North America.
No one would say that the United States of Mexico is anything other than a single nation under one flag, yet that is its official name. That each of the states in America has its own flag is a holdover from the time when each was an autonomous nation. That is simply no longer true. The state flags are an obsolete artifact of a bygone system.
"States" is even a misnomer. They are no longer states in the way England is a state or Germany. They are districts of a single, unified nation. There is only one "state" between the Canadian and Mexican borders. That is the only state with rights.
Any other "states rights" are obsolete and stopped being of effect in 1865.