They would try to control what you could or could not do with the resource. Look at food as an example. In the US food is an essentially unlimited resource in that we produce far more food than we could possibly eat and most people have access to more than they eat. So now they try to control it by telling you what you should eat and how much. Excess is a problem they say has to be solved.

 

Politics is about power and control. Right now, resources are the leverage. If that were to change, they would find different leverage.

Someone cares for a third opinion? I think it depends on how this energy is accessible. If it is possible to use it easily, like that everyone could have it, probably politics as known today would vanish. If there were no more struggle on the economy, what do I have to regulate to? But I think, as said, that we could die for the excess, so probably that's where a new politics would arise, one that would be like a global moral conscience that would block us from hurt the others -- and there's nothing new here -- but in a different way, which paradoxically would be achieved walking on the same path as the one needed today: awareness. Hope I have not been too philosophical, it wasn't my intent.

It'd depend on the source and its accessibility, as well as the inherent difficulty in aquiring and refining it, and what dangers were part & parcel.
If it was everywhere and simple to use and as non-dangerous as water, then it's rather impossible to predict much more than a population explosion, which would eventually result in fighting over land.
If it was controllable or potentially dangerous, then it would be controlled and a new product would debut on the black market. Wars would likely be fought over it.

 

I would not say land per se is scarce.  It is land that is capable of being productive.  If we could, at will and at little to no expense make any land we want productive, energy so cheap it would be virtually free, water easily available, be it through creating, finding or producing a limitless supply of drinkable water, even find a way to rid ourselves of all deadly viruses, able to correct birth defects and other afflictions of health cheaply, that is what I am referring to.  How would politics change?

 

Something to note,....a simple perusal of history shows that innovation and human progress does not happen until it is forced.  As populations increase and a demand for resources has forced a change.  Prime example, look back when whale oil was starting to become scarce, along came coal oil and later petroleum.  Likewise, with the innovation came in food production.  Today, there is more production of food grains; more bushels per acre than ever and it is done with fewer people and it costs in relative terms less now than it did 100 years ago.  Likewise if history is any indicator, we will eventually end up expanding one day beyond our planet.  If I am wrong, we are screwed anyway and it won't matter. I tend to think that human beings will solve the problems.  At some point, the technology will exist on a planetary scale to make energy production virtually free, perhaps by using orbiting solar arrays beaming the power to a dispersion point.  As for food production, there are already innovations in such things as Urban gardening and other kinds of food production that are new and showing promise yet are in it's infancy.  I am not gloom and doomer on the long term.  The human race has survived as humans at least a million years and our ancestors have had to be very clever and intelligent to do so.  I have no doubt we will continue to do so.  That doesn't mean we many not suffer setbacks but long term, I would bet the farm on it.