"for it was the individual state that ratified the U.S Constitution and accepted it as its law independent of other states."

False. The people,not the legislative body of the individual states ratified the Constitution. Where else would they ratiftiy them?

You see the 10th Amendment was created three years after the ratification of the Constitution, after a federal government was already in place. And the 10th has never possessed the power that anti-federalists would give it. As the Constitutional Convention convened to write the Bill of Rights, the delegates by a 2-1 margin (32-17) rejected adding the word "expressly" to this amendment which might have given it the power anti-federalists crave for it. This rejection makes it clear that it was up to the people themselves, as expressed by their elected government to decide in what ways the federal government would apportion power to the states. Out of many one. Not fifty.