Did FDR follow the constitutional laws

This is a difficult question to answer.

When FDR was first elected, he proposed a variety of programs that were designed to combat the Great Depression. These programs were rejected by the Supreme Court.

FDR was upset by this rejection and tried to pack the Supreme Court with his allies. That failed.

FDR eventually got the Court he wanted when Supreme Court justices died or retired and then FDR's programs were suddenly Constitutional.