Could someone please explain the importance of citizenship in Medea. How is Jason's marriage to Glauce advantageous to his children? What is Medea's deficiency?
In rudimentary terms:
You is Greek; you is good.
From memory (its been about a year since I touched any background info on Medea though so I may be slightly misinformed):
Ancient Greece was quite a xenophobic society; anyone who wasn't of Greek ethnicity was considered barbarous and an outsider. The Greeks held the view that to be Greek was to be civilised and everyone else couldn't possibly be civilised because they weren't Greek. Medea was from Colchis (i.e. not Greece) and as such she was considered uncivilised. So for Jason it was a matter of choosing between Glauce, the hot new GREEK thing who could enable him to advance his station and status and blah blah blah or Medea, the non-Greek psychopath who'd literally turned her back on everything for him and ofc, he made the obvious decision to choose Glauce the Greek princess. So long as he was with Medea, he couldn't have legitimate Greek sons because in order to gain Greek citizenship then, I think you needed both parents to be Greek citizens?? (Would check for you to be100% sure but dodgy internet atm)
How is Jason's marriage advantageous? You could argue that much of the part where he argues he had the best interests of his sons and Medea at heart is just rationalisation as he seeks to justify an action that he, to some level, recognises as wrong. From memory, much of his dialogue with Medea when he first arrives to speak to her is quite structured and he uses stuff like "Firstly...","Secondly...", etc which suggest that his argument/justification was someth he'd planned out or at the very least someth he'd mulled over quite a bit to come up with such a coherent and 'reasonable' argument, suggesting that maybe on an emotional level he realises that his actions aren't really that advantageous if he feels the need to justify them and mull them over to himself and his wife.