Unfortunately, as the author writes, the PA is becoming irrelevant and Hamas is gaining support as a result of the political changes in the region and the recent violence. Old "understandings" between the PA and Hamas on how to handle negotiations with Israel (which Israel was never amenable to) will likely have to be reworked, as Hamas finds itself in a position of strength which respect to Fatah and the PA. Officially, only the PLO can conclude an agreement with Israel on behalf of all Palestinians and right now, Hamas is not a member of the PLO. Abbas and Fatah have kept them out. But this will likely change in the future. If Israel chooses to negotiate with a reformed PLO, Hamas will have a say.
Yemen's Houthi rebels commit to peace plan in letter to UN chief, BBC reports (Haaretz)
from the article: Endgame for Israel and Hamas - but what comes next?