That's incorrect

What is incorrect with what I said? It is undeniable that the states voluntarily joined the union when the Constitution was created, as each state literally voted on whether or not they would accept the Constitution and join in a new union with the other states that voted to accept the Constitution.

It is also undeniable that the states would not have ratified the Constitution if they believed that they could never leave. After all, each of the states independently voted to succeed from the British Empire. They eventually formed a confederation under the Articles of Confederation, in which there had to be unanimous consent among the states for the government to act. After this, was the Constitution, which was the creation of delegates sent by the states to discuss changes to the Articles. After the Constitution was drafted, it was up to the states to decide if it is ratified or not. In effect, the states created the Constitution, created the federal government, which was to act on their behalf, and put the Constitution into force.

Aside from the fact that the states created the Constitution and the federal government, there is the fact that the senate was literally the legislative body of the states, with the state legislatures choosing who would be the Senators for their state. The federal government was unable to take any action or pass any legislation without the approval of the majority of the states. The Senate also had power over presidential appointments to federal agencies, the military, and the judiciary, giving the states the ability to control who held what positions in the federal government. All spending and taxation also had to be approved by the Senate, meaning the federal government could not spend money or impose taxes without the approval of the majority of the states.