Strange to read this from Avineri, who is usually more thorough. Note that the word "Hamas" does not appear in this article. And all he gives us is "Moreover, if Palestine were independent, Israel would have no responsibility for the Gaza Strip..." But this has no connection to a unilateral declaration of statehood. Reality says there would be two declarations - one by Fatah and one by Hamas. There would be two Palestinian states - one in the west bank and one in Gaza. The two Palestines would most likely have a civil war on their own turfs, and there would be an intractable divide in the Palestinian arena. The Iranians and Syrians would recognize Hamas, the Arab League would recognize Fatah. The United Nations would do nothing (as usual). Chaos would reign. Strange that Avineri doesn't deal with the real outcome of such a declaration.
from the article: What would happen if Palestinians unilaterally declared statehood?