Added that Congress has the ability of subpoena power that can override any sitting president.
They can call even the president to the bench for questioning.
Here is the thing, what is going on now is basically Trump admin are trying to delay the inevitable, that report is coming out and will not show Trump in a positive light, the goal is to hold it off as much as they can. The next AG for the next president can release this stuff but they want this off record until after Trump's full term is over and that is why the rhetoric you hear that "there will be no peaceful transition of "power" should the Dem nominee wins the presidency, it is not about election fraud it is about delaying this release of this report as long as possible.
They are trying to sell their sheep on this clearing Trump but truth is it will incriminate him, and his people and many others that will be collateral damage. Mueller is a complex type person, when he says "no further indictments" on his part does not mean future indictments are not coming, it could by a different branch like State authorities who has jurisdictional rights to such material and prosecute on a state level.
Also, not finding "collusion" that warrants an indictment is different than no collusion was found. On most cases, such reports uncovers unrelated crimes and has to be dealt with. Most indictments Mueller came out with were obvious crimes found during the investigation but had nothing to do with collusion but are still criminal acts. It is legal to prosecute other crimes not related to collusion found as a result of this investigation. Most Trump supporters do not get this...
Trump is acting nuts because that report contains damaging info and can cause humiliation and they do not have to be crimes in itself but will reveal many unethical practices that went on. They can spin "no collusion" to the choir but this is going to be damaging...
There are technicalities that can prevent the gov't to prosecute Trump at the current time does not make him innocent of all charges as well...