It is important because it establishes the constitution as the supreme law of the land. That means that every person, regardless of their social status, and every state, regardless of their wealth or size, have to obey the constitution. If the supreme court says that something is unconstitutional then it will never be able to exist, and if they say that something has to be done then it will have to be done because of the constitution.
The answer is when teachers began to start educating and training their students at school! I hope this helped :D
The general basis for forming the Republican Party was "<span>C. uniting several Northern antislavery coalitions," since the Republicans broke away from the Whig Party for this purpose. </span>