Why doesn't Ismene bury Polyneices instead of Antigone?

Ismene is too intimidated by Creon. She believes that he will make good on his word to execute anyone who buries Polyneices, and she is afraid of getting caught and being put to death. She is more of a rule-follower than Antigone is, though Antigone is only breaking the law out of love for her brother. She is worried about Antigone, as well, and asks her not to bury Polyneices.