Israel's urban planners have tended to stress short-term considerations at the expense of long term environmental and historical treasures. Now, Jerusalem is faced with a decision: whether to expand the capital's limits westward toward the forest and the suburbs of Mevessaret Zion or eastward, over the Green Line, toward the settlement city of Ma'aleh Adumim. The Safdie Plan - to expand Jerusalem westwards - would deface a uniquely breathtaking landscape, the capital's beautiful landmark gateway. It calls for constructing 20,000 housing units on about 26,000 dunams of woodland. It would become one of the largest construction projects ever attempted in the country, placing apartment-house complexes where green forests now tint the vistas. Which is why we empathize with the concerns of movements such as the Zionist Council of Israel, a good government group, which has come out against the Safdie Plan. A ZCI study group comprised of experts and public figures of all political hues has warned that the plan which purports to solve Jerusalem's housing shortage would weaken its downtown, while damaging its peerless natural surroundings. On the face of it, indeed, the Safdie Plan would seem to raise concerns as acute as those posed by plans to build on lands reserved for the Ayalon Park between Tel Aviv, Ramat Gan and Holon, plans which were thwarted last year via a special Knesset bill. But when it comes to Jerusalem, the issues go beyond housing, environment, smart urban planning, or the preservation of "green-lungs" regions, which are now being systematically whittled away. This isn't yet another tug-of-war between those who support unbridled development and those who favor quality of life and the great outdoors. For if the nation's resources are invested in expanding the capital along the lines the Safdie Plan advocates, we will be simultaneously deciding not to expand in the other direction. There are insufficient political and financial resources to do both. And Jerusalem desperately needs to expand one way or another, not least if the capital of the Jewish state is to reverse its dwindling Jewish demography. The principal alternative to the city's westward expansion toward is the expansion of Jerusalem eastwards, according to the popularly dubbed E1 Plan. This plan, raised and shelved repeatedly over the years, would link the capital with Ma'aleh Adumim, and provide an important buffer zone. Such construction would also secure one of the country's key settlement blocks, a community of 32,000 souls. Solidifying such major settlements under Israeli control is widely supported by the Israeli public. And while the American government formally opposes all settlement construction, it was President George Bush who said: "It is unrealistic to expect that the outcome of final status negotiations will be a full and complete return to the 1949 armistice lines." American and European Union pressure has to date dissuaded a succession of Israeli governments, including that of Prime Minister Ariel Sharon, from going ahead with linking Jerusalem to Ma'aleh Adumim. Opponents of E1 argue that it would torpedo prospects for a viable Palestinian state by making it impossible for Palestinians to travel from Bethlehem to Ramallah. But surely a solution that allows Palestinians a north-south transit, while linking nearby Ma'aleh Adumim to Jerusalem, is hardly beyond the creative capabilities of diplomats and transportation planners. Perhaps one means for the Sharon government to assuage international opposition to E1 construction would be to simultaneously move vigorously to finally dismantle the illegal outposts in the West Bank - as it promised it would. In any case, with the Knesset election campaign now underway, all parties owe it to the voters to tell us unambiguously where they stand on E1 - the more so as a decision not to build there would appear to represent a decision to proceed with the Safdie Plan. The front-running Kadima Party of Prime Minister Sharon has a particular obligation to tell the citizenry its policy on E1 and how it proposes to address Palestinian and international concerns over it. And those parties that oppose E1 need to explain how they will nonetheless keep Jerusalem secure and vibrant and Ma'aleh Adumim accessible.