Economic War with Earth

OK, lets step back a minute: why would issues come to a head? What could
either side want that they require from the other? Off the top of my head:

Habitats: volatiles, especially if they operate a relatively open-loop
environmental system - but couldn't they mine the poles of the Moon?
Economic markets: maybe?

Nations on the Earth: Solar satellite power - maybe, but building more solar
panels or wind turbines might also do the trick. Economic markets: rather
unlikely for the first coule of decades?