Early Saturday, Hamas fired thousands of rockets into Israel as its fighters poured across the border from Gaza, killing hundreds and taking others hostage. In response, Israel declared war on Hamas and began retaliatory strikes on Gaza, also killing hundreds. WSJ’S Dov Lieber on a “game-changing” moment in Israeli-Palestinian relations and what comes next.  Further Reading: - Iran Helped Plot Attack on Israel Over Several Weeks  - Israel Readies for Ground War in Gaza  - What is Hamas? What to Know About the Militant Group Fighting Israel  Learn more about your ad choices. Visit megaphone.fm/adchoices