Arrests need probable cause. They can either be done on a warrant or without a warrant (in the latter case, in the federal system, a complaint must be filed and the arrested person must be brought before a magistrate for a hearing on probable cause within 72 hours after arrest.)
The president can replace them.
The judiciary has zero enforcement power. They make the laws which the executive is meant to enforce. If the executive fails to enforce a law, congress can impeach. That's not happening.
The executive branch runs the country.
The legislative branch makes the laws.
The judicial branch enforces them…
The current executive branch will not enforce laws against itself, and nobody else is legally allowed to enforce the laws, so all the courts & congress can do is write strongly worded letters.
Yknow… the branch that’s supposed to check the power of the executive branch…