The reason the framers of the constitution stipulate that federal judges be appointed is to make judges independent of public opinion .
Explanation:
Framers have been the innovators of the American constitution. They are built to survive the Constitution. They sought not just to resolve the particular challenges of their life but also to identify the basic principles that would help and lead the new country into an unknown future.
The key idea was to separate judges from the political and democratic system.
Both the Senator (representing State legislatures) and the President shall assist in the declaration.
Therefore, both the Legislature and the Executive are judged by the appointed Judge but are separate.
They help to discourage political change forever; we must not be scared of being changed if they are not accepted by an official.