One of the many ideas around reform of the US Constitution is the repeal of the 17th Amendment. The 17th Amendment essentially changed the election of US Senators from a vote of the State Legislatures to a vote of the people.
A repeal of the 17th would essentially restore and reconfirm the role of the US Senate as a state’s house.
There are clearly arguments against a repeal, hence the amendment in the first place and arguments for, hence the current arguments for repeal (hows that for circular logic!).
But what would happen in Australia if the Commonwealth Senate were to be appointed by State and Territory parliaments? It would (probably) have to be aligned with State and Territory elections, but irrespective. I wonder ….