Let's say Hunter Biden was a hit man for Bursima and not just money laundering bribes for his father, would it be legal (non-impeachable) for Trump to ask for help to investigate?
#5 | POSTED BY VISITOR_
Depends. Being a "hit man" is not illegal. But, I am assuming you mean to say that he murdered someone. In that case, it depends on jurisdiction and where it happened. If it happened in the US, then the DOJ should open an investigation and try to build their case. If they think that Ukraine has relevant information, then they should request it (I believe a treaty with Ukraine where we agree to provide assistance to each other's investigations). If they request it, and they are either rebuffed, or just do not think that Ukraine is forthcoming, then they should put in a request to the State Department for help in getting the Ukraine's cooperation. Then, if the State Department thinks it is necessary and of sufficient national interest, they can request that the President directly request Ukraine's cooperation.
If the US does not have jurisdiction (it did not happen in the US and cannot be connected to US regulated entities) then it becomes murkier. If the US has a clear national security or policy reason to have him prosecuted, then the President could request that Ukraine prosecute him (I could see us doing something like that with an international drug dealer or spy or something).
But, since this hypothetical is related to Biden (who is a presidential contender), you would want to make sure you had a long and detailed paper trail showing that everything was done for the right reason and that every 'i' was dotted and 't' was crossed, because you would STILL get accusations that you were abusing your office to attack a political opponent. As an example of that, look at the Obama administration's investigation of Trump. They DID do everything by the book (it was an official investigation, Obama did not get personally involved, contacts with foreign governments went through the proper channels, and Obama wasn't even running in the election) and STILL conservatives claim that it was politically motivated.