Rarely have terrorists chosen their target with so much malicious care as in Thursday night's attack on Jerusalem's Mercaz Harav Yeshiva. In striking the flagship institution of the religious Zionist movement, a Jerusalem landmark whose history is linked with the founding and fulfillment of the Jewish national home in the Land of Israel, the gunman aimed his weapon at the heart of the Zionist enterprise. If the goal was to outrage the general public and to inflame that particular segment of it most skeptical of the possibility of Israel one day coming to terms with its most immediate Arab neighbors, then the bullets struck home with deadly and accurate force. Beyond that, as the first terrorist attack on this scale in nearly two years - since a Tel Aviv suicide bomber killed nine in April 2006 - the impact of this incident will be profound. This will be a sharp blow for those Israelis, especially Jerusalemites, who have allowed themselves to let their psychological guard down since the second intifada petered out. That the gunman was able to carry out this operation in the heart of a crowded Jerusalem neighborhood, some distance away from the Arab neighborhoods of the capital, will raise serious questions about assumptions made since the construction of the West Bank security barrier. The Olmert government, which until now has been able to contain political fallout from the rocket fire on Sderot and Ashkelon in part because of the absence of major attacks elsewhere in the country, will now find its margin of error - and survival - dramatically narrowed. The efforts by both Jerusalem and Washington to renew the negotiations with the Palestinian Authority, interrupted by the fighting in Gaza, will now be officially put on hold, and picking up the pieces in the wake of this outrage will not be easy. The grief and fury in particular of the religious-Zionist sector will be beyond measure at this violent desecration of the cradle of their movement. The current efforts by the government to reach an accommodation with the settler leadership on the removal of outposts will have been in vain for the time being, as any spirit of compromise will be buried with the victims of this atrocity. Israel's radical Islamic enemies - Hamas, Islamic Jihad or Hizbullah - have talked in the past month about dealing a blow to Israel that would go beyond any of those they have carried out before. The death toll last night was nowhere near the worst of those attacks they have carried out in the past. But in bringing their war of terror right into the halls of Mercaz Harav, the institution founded by and embodied with the spirit of the Zionist's movement's most revered religious figure, the Yishuv's first Ashkenazi Chief Rabbi Avraham Yitzhak Hacohen Kook, the terrorists struck with the most terribly precise accuracy they have demonstrated to date.