You get emNo, it's not. While I understand and respect the spirit of this noob's first post, it's factually incorrect. Specifically:
While the chances of an amendment being repealed (the 2A, for example) are extremely small, it is possible. And it can be done without a Constitutional Convention. It needs to be proposed in congress and then ratified by 3/4 of the state legislatures. It happened before with the 18th Amendment.
The Constitution provides for a way for the Constitution to be amended in Article V.