First, I would re-engage the PA in peace negotiations, and achieve something. Maybe continue where Barack, Arafat, Clinton left off. Once something is moving, Hamas might feel left out. Maybe, after the Israeli elections this coming January, Obama should travel to Israel and the recently acknowledged Palestine, then send (just a thought) Bill Clinton and Alan Dershowitz to introduce/develop new "parameters". Yet, I doubt anything can be achieved untill Israelis chose new and different leaders ...
U.S. Democratic Sen. Bill Nelson announces support for Iran nuclear deal (Haaretz)
from the article: It's time for Israel to talk to Hamas