Actually prior to the threat they stated that they would approve it as fast as possible and were targeting Saturday morning. Trumps bullying sped things up by about 12 hours.
Note that the approval date has absolutely nothing to do with the production schedule, which is the real limiting factor here. Having a few hundred people get their shots on Saturday instead of Tuesday or whatever isn't realistically going to move the needle. Every dose we can get is going into a patient somewhere.
I saw on the news today that the vaccine was sitting waiting for the approval to ship. So yeah, getting approval sooner will get the vaccine shipping sooner.
Scale-up work and production started at the end of the summer.
Yes, and every dose produced so far is ready to go into a patient immediately, they don't have a stockpile for the whole society, not remotely. Two days or whatever isn't going to matter that much. The timing of the first few thousand doses will change, the timing of the first ten million doses has to do with production and shipping, not approval.