A window will re-open (maybe permanently) when the majority of humans live in space habitats. Because of the long distances between habitats[1], the relatively small populations of each[2], and the fragility of the habitat[3], I expect local governments to be more responsive to their citizens.
[1] parent nation takes longea to respond with overwhelming force/more time for local rebellions to solidify control
[2] not enough population to sustain a large garrison but also easier to get a significant portion of the population engaged.
[3] catastrophic sabotage is easier so discontent must be addressed more proactively. Also external applications of force may be limited to massacre or siege since boarding a hostile ship becomes very dangerous.