On the narrowest of margins does history turn. If the Spelman amendent had been defeated (and it would have taken just two MPs voting the other way for that to happen), the most likely outcome might well have been a No Deal Brexit, either on the scheduled date this month or after a very short last-ditch extension. As it is, Theresa May has clearly shifted her ground and started to countenance the possibility of a longer extension. She did it in her customary "nothing to do with me guv" sort of way, but the change is real - before tonight she was definitively ruling out an extension of more than a few weeks, while now she is accepting that it could be an unavoidable and unwelcome consequence of parliament's decisions.
Which seems to leave us with a binary choice between a) the Brexiteers being spooked by the threat of delay into voting for May's deal at the third time of asking, or b) an Article 50 extension of sufficient length that the UK would be forced into taking part in the European elections in two months' time. (Admittedly the latter would cause such fury among Brexiteer MPs that the government might well be toppled.) Either way, a moment of truth is coming for the independence movement - the passing of the deal would mean that the clarity Nicola Sturgeon has been awaiting would arrive imminently, at which point we could expect a decision about an independence referendum. Or if the European elections are held in Scotland, the SNP would presumably use them to attempt to further reinforce their mandate for an indyref - with a good result being vitally important.