The Framers made it difficult to amend the Constitution because a constitution is not really worth much if it can be changed easily. A constitution is supposed to represent the fundamental law of the land. It should not contain laws that have been put in on a whim or that are not about important issues. If it did, it would be just like any statute passed by a legislature. For this reason, the Framers made it hard to amend the Constitution.
There are two different ways in which the Constitution can be amended, though only one has ever been used. The first method is to call a constitutional convention. Two-thirds of the state legislatures would have to call for such a convention and three-fourths of the legislatures would have to approve any proposed amendments. This has never been done because people are leery of calling a convention that might propose a number of amendments and thereby change the Constitution in unforeseen ways.
The other way to amend the Constitution is for each house of Congress to vote to propose an amendment. Two-thirds of each house would have to vote in favor. This would not be a law and so the president would have no veto power. Once the amendment passes Congress, it goes to the states and three-fourths of the states must approve in order for it to be ratified. You can say that this is two obstacles (passing Congress and passing the states), three obstacles (passing each house and passing the states), or 41 obstacles (passing each house and passing 38 states).
In my view, this difficulty helps to protect democracy because it makes it harder to take rights away from people by amending the Constitution. For example, an easier amendment process might have meant a constitutional amendment to ban gay marriage a decade or so ago.
I do not think that the Framers’ intention has been undermined by things like the elastic clause. The elastic clause does not allow the government to change the most important parts of the Constitution. It has allowed the powers of the federal government to grow relative to the states, but it does not allow changes in really fundamental aspects of the Constitution.