Here's the story Paris was brought forward to judge out of the goddesses who was the most beautiful, Maybe it was who Aphrodite bribed Paris if he picked her he could get any girl he wanted, or Paris took the deal and chose Helen, and under Aphrodite influence and she ran off with Paris. Or Helen was the fault for running off with Paris. It could be Agamemnon who wanted war and Paris running off with Helen was the perfect chance; or you could blame Menelaus for being a cruddy husband you would have a lot of choices.
Hoped I helped:D