is contracted, although this is not stated outright. Medea is furious because she helped Jason significantly during his travails with the Golden Fleece, but Jason's only response is that he has to marry a Greek woman, so unfortunately this cannot be Medea. She replies that she’s left everything—family, homeland, language, gods—to be with Jason, and he’s casting her aside without ceremony. Jason effectively tells her to calm down and get over it.

In response, then, Medea feels she can only punish Jason properly by taking everything away from him in order to impress upon him her feeling that everything has been taken from her. She achieves this by poisoning his new wife, murdering his children (whom he presumably was going to disinherit in favor of his new legitimate children), and then running away to Athens to marry the king there. She takes the children’s bodies with her so that Jason can’t even hold them or bury them, and she makes a point of saying she’ll bury them by Hera’s temple—Hera being the ultimate representation of the wronged wife in Greek mythology. She didn’t want to kill the children, but she wanted to make the point that she lost everything to be with Jason, and since he no longer cares, she’ll rip everything away from him.

Medea would have done anything to be with Jason. These aren't just words; she backed up her passionate love for Jason with action——namely killing her own brother Absyrtus before she fled Colchis with her beloved. But now that he's betrayed her, gone off to marry Glauce, she will do anything for revenge, even if it involves killing her own children. The intensity of Medea's love is matched only by her hatred towards the man she once adored.

Medea's actions could plausibly be justified on the grounds that she's an instrument of divine will. Her falling in love with Jason was the work of Aphrodite or Eros, so Medea, as with so many mortals in ancient Greek myth, is a pawn in a much bigger game being played by the gods. Medea's killing of her children, though utterly reprehensible from the standpoint of human morality, does appear to be sanctioned by the immortals, and Medea knows all too well what happens to those proud or foolish enough to defy the gods. Indeed, one could argue that it is Jason who has offended the gods by dumping Medea and entering into an unfaithful relationship for purely political advantage.

This impression is confirmed by the deus ex machina that helps Medea to evade justice at the end. The chariot of the sun-god Helios swoops down, whisking Medea away along with her children's dead bodies. We may look askance at Medea's despicable acts, and not just in relation to her children, but the gods clearly smile upon her. And ultimately, for the ancient Greeks, that's what really matters.

I think that this particular action is where Medea ends up moving into a realm where her actions are indefensible.  In her mind, she sees it necessary to kill Jason's sons for a couple of reasons.  One of the reasons she uses to justify killing the children is because of pragmatism.  Medea figures that "the Corinthians will kill the children anyway, in retaliation for her murder of Creusa and Creon."  This aspect of practicality in Medea is one reason she uses for her actions.  Another reason is out of pure spite and wrath towards Jason.  When Jason indicates to her that she will suffer as well, Medea argues that this experience is secondary to her being able to take from Jason.  The anger that is felt towards Jason compels her to kill the children.  In another respect, Medea represents the idea that the emotional experience of jealousy and vengeance can be all encompassing, one that knows no limitations.  Civil society would regard the killing of children as one of the worst crimes and a point from which there can be no return.  Yet, Medea's jealousy and rage, her feelings of hurt caused by Jason's action, causes her to be irredeemable and past that point, demonstrated by the killing of her own children.

Euripides' Medea, first staged in 431 BCE, was one of the most horrifying plays to come to the ancient Athenian theater. In the play, Medea is responsible for the deaths of Creon, Creon's daughter, and her own two children by Jason.

On one level, it is difficult to find any excuse for Medea's actions. Even though Jason divorced her, Medea had arranged for protection with King Aegeus of Athens after leaving Corinth, so there was no issue of Medea being "cast out into the cold" with nowhere to go. Additionally, Medea's children are completely innocent and so killing them is morally reprehensible.

From the perspective of the mythic tradition, Jason survives his encounter with Medea and so to have Medea kill Jason would have run counter to the established tradition. So, that sort of revenge would not have been "right" from that perspective.

Although in my view Medea's actions are in no way "right" in a moral sense, her revenge on Jason could be seen as "perfect" if we take this word to mean "complete" or "whole." So, if by "perfect" we mean "complete," then I would say Medea's revenge is "perfect."

Medea kills the children that she has had by Jason, so Jason no longer has male heirs (the ancient Greek version of a 401k plan). Medea kills Jason's new bride, so he cannot produce heirs by her to replace his dead sons. Medea also kills Creon, so Jason is not going to be able to inherit his kingship. Finally, Medea leaves Jason alive to carry out the rest of his wretched existence with the memories of how Medea, in a matter of minutes, wiped out everything he loved and everything he dreamed of.