Worrying about something a bit prematurely
I have serious doubts about Elon getting to Mars. Financially more than anything else. There just isn't a commercial rationale behind a manned mission to the red planet. Mars is also a destination that will need a tremendous amount of prep before humans set foot there. The Mars trilogy by Kim Stanley Robinson covers a bunch of the issues, but glosses over a whole bunch more. The hardware isn't a problem, humans are.
If it becomes viable to mine asteroids, there will be some country in the third world that passes law making it all nice and legal (or at least unrestricted) with no regards to NATO, US, Russia, China regulations. A country such as Ecuador could do nicely and attract a big aerospace industry presence by giving the bird to any other country that doesn't like it. This parallels medical research and therapy. If cloning becomes mainstream (organs/body parts, not complete people) and it's banned in the first world, those with the money that would benefit would move to wherever those procedures are available. Medical travel is already a thing to save money on certain surgeries.
It will be a long time before there is competition for specific resources/space objects between two or more companies. There will be one company that gets there first and it could be found to be too expensive or risky. Do we want politicians to be spending what little time they actually put in at work debating policies that may not be applicable for decades? Looking at the ages of the candidates in the next US presidential election, only a couple may be alive when the next person steps on the moon. Zero may be around when a private company figures out a way to mine an asteroid for a profit. Never mind two.