Numerous states allow citizens to vote to change their state constitutions. Should the process of amending the US Constitution follow a similarly easy process? Or should amending the US Constitution be made more difficult than it is?

The process of amending the Constitution is long and complex—and intentionally so. The Founding Fathers saw the Constitution as a bulwark against any kind of hasty, ill-thought-out policy measures that might undermine the principles on which the American Revolution had been fought. Essentially, they wanted to lock in the political ideals that had made ratification of the Constitution possible while at the same time still allowing the American people to make changes. To that end, Article V of the Constitution stipulates that an amendment can only be made with the support of three-quarters of state legislatures, or ratifying conventions in three-quarters of the states. This provision guarantees that any proposed constitutional amendment must clear a substantial hurdle if it is to succeed.
Some have argued that the amendment process needs to change. Critics insist that it's too slow and cumbersome, making it unable to respond effectively to changes in public opinion. The failure of the Equal Rights Amendment is often cited as an example of this. Opinion polls showed a clear majority in favor of the ERA, yet due to the opposition of a mere handful of state legislatures, the proposed amendment failed.
The case of the ERA illustrates the biggest problem with the amendment process: it requires a level of consensus that is almost impossible to achieve. During the late eighteenth century, when the Constitution was first ratified, the United States was a much more homogeneous country than it is today, with a much smaller population. This meant that it was much easier, though still by no means easy, to reach consensus on proposed constitutional changes.
However, in this day and age, things are completely different. The United States, as well as having a much larger population than it did in 1787, also has a much more diverse, more deeply polarized society than it did back then. This makes it all but impossible to clear the very high bar that Article V sets for constitutional amendments. The late Supreme Court Justice Antonin Scalia estimated that it would take less than two percent of the American population to thwart a proposed amendment. As he further went on to say, the process should be hard, but not that hard.