As far as a possible in universe explanation on the Republic/Resistance/First Order situation… It could be that the New Republic, like the Old Republic prior to the Clone Wars felt that they shouldn’t have a standing army and the plan was to have Luke rebuild the Jedi order to once again be the guardians of peace and justice in the galaxy.
So due to past mistakes, the idea of raising an official military for the republic could just be something they see as politically unacceptable and hence we get the Resistance which rises up independently to the fight the First Order after a few initial terrorist type attacks on Republic systems. The Resistance effort would then be secretly supported by the Republic and as stated above it isn’t too hard for the First Order to connect the dots.
That’s a pretty good explanation. I can buy that. But hopefully they’ll explain at least a little in episode VIII because that’s a lot of assumption.
As I’ve said, I’m not looking for prequel-style exposition (I loathe the prequels), but a quick ‘the republic is peaceful, they renounce war and relied on the formation of a new Jedi order.’ would help. Not everybody reads EU (although I just ordered Lost Stars, I’ve heard it’s good).
The Republic probably initially just didn’t think the First Order to be much of a threat with Vader and the Emperor gone. You’d think that once they destroyed the new Jedi order that should have changed… do we have any idea how long ago that happened and how long Luke has been missing?
Well Adam Driver is 32 years old… so even if we assume Ren is the same age as the actor who plays him, his fall to the dark side and the subsequent destruction of the new Jedi Order couldn’t have happened more than what… 20 years ago? So in 20 years the Republic never once thought ‘maybe we should do more about these ‘First Order’ guys than give Leia a few ships’.