Considering all of the political implications that will result from this appointment, why has Congress never established a date in writing to determine once and for all whether the sitting President or the newly elected President will make the appointment in an election year?
We went through the same arguments in 2016 when Justice Scalia passed away. At the time President Obama made a nomination and the Republicans argued that an appointment should wait until after the election. Four years later, the two parties are arguing the opposite of what they did in 2016.
Why doesn't Congress establish a date, say June 1, so there is no arguing? Any vacancy that occurs prior to June 1, the sitting President fills it. After June 1, we wait until after the election.