"Constitutional crisis"
One party is saying that Trump will create a "constitutional crisis" if he fires members of the executive branch.
There can't be a crisis because we haven't had a constitution since 1803.
But: Assuming for argument that a constitution still exists, this is obvious nonsense. The president is CEO of the executive branch. He can hire and fire ANYONE he wants within the branch. Normally a CEO doesn't hire and fire low-level clerks anyway, so this practically means that he's supposed to hire and fire top bureaucrats, who then supervise the lower levels to suit the desires of the CEO.
What's obviously contrary to the organizational chart? Members of the executive branch (like FBI and CIA) attempting to bring down the CEO because he belongs to the wrong party. In any organization, middle executives who try to bring down the CEO are fired.
Who is supposed to monitor and inspect the President's behavior? Congress. Here the constitution is quite specific and detailed. Congress can defund any executive activity it dislikes, and Congress can impeach both judicial and executive officers including the president.