There's a bitter joke going around Israel concerning President Obama's feckless response to the current fighting in Gaza. "Obama says he wants to negotiate a cease fire between Israel and Hamas," Israeli cynics observe. "Bibi Netanyahu should agree, on the condition that he gets to negotiate a cease fire between America and Al Qaeda." The point is that everyone knows a true cease fire is impossible with Al Qaeda: they don't want America to compromise or change, they want America destroyed. By the same token, Hamas isn't launching hundreds of rocket attacks because they want Israel to change, or to alter specific policies. They demand the Jewish state disappear, as their charter proudly declares.
When facing an existential challenge, negotiation is meaningless, for America or Israel. Terrorist groups pledged to your destruction can't be appeased. They must be defeated, or at least strictly limited in their ability to do harm.