The murder of four Israeli settlers on the eve of talks rattles leaders. Hamas claims responsibility and Ha'aretz says they have succeeded in embarrassing the PA. Israel seals off Hebron. The PA condemns the attack and arrests scores of Hamas militants. Nahum Barnea says it strengthens PM Netanyahu's hand in negotiations. Tom Friedman says Pres. Obama's efforts at stability in Iraq and Palestinian-Israeli peace are a uniquely ambitious combination and Bloomberg suggests these efforts may be aimed at countering Iran.. Pres. Mubarak says peace is possible. Pres. Abbas reiterates his commitment to peace. DM Barak suggests a compromise on Jerusalem including a "special regime" for tbe old city. US officials again say peace can be reached in a year. New statistics suggest reduced settlement activity in the first half of 2010. Ian Black says neither side seems ready to make serious concessions on peace. Rami Khouri says the US may be waiting until December to seriously pressure the parties. Hussein Ibish says a new book on "the Arab lobby" is comically wrong.