> The court didn't find that Whitmer acted arbitrarily or capriciously, they simply ruled that she lacked the authority for the actions she took.

Specifically, it found that that emergency powers act under which she acted was an unconstitutional delegation of legislative authority; the fundamental error the Court found was by the legislature, in not crafting an emergency powers law with sufficiently defined boundaries (or, alternatively, by not availing itself of the process to amend the Constitution to create broad emergency powers.)