Something curious has been going on at the Karni crossing between Israel and the Gaza Strip. Until this week, that crossing - popularly dubbed "Gaza's lifeline" - had been closed for more than two months due to a succession of alerts about an imminent major terrorist attack. Amid concern about a looming humanitarian disaster if basic supplies could not be transported from Israel into the Strip, Israel agreed to allow in goods via the Kerem Shalom crossing, and spent heavily to ensure that this crossing could be operated effectively. But the Palestinian Authority rejected the Kerem Shalom option. On Monday, despite the ongoing terror warnings, Karni was unexpectedly opened, but closed half-an-hour later. Yesterday it reopened. This strange sequence of events suggests Israeli irresolution and muddled thinking. In an interview with The Jerusalem Post yesterday, Defense Minister Shaul Mofaz asserted, on the one hand, that there was indeed a real terror threat at Karni but, on the other, that the partial and intermittent opening of the crossing has been achieved without compromising security concerns. Mofaz added that Karni was closed down so rapidly on Monday because its opening prompted an immediate effort to carry out a terror attack there, and that it would be closed again should a similar danger recur. At the same time, Mofaz also acknowledged, as a factor in government decision-making, the fear of an international backlash against Israel prompted by scenes of Palestinian suffering. This begs several questions. Among them: If the threat to Karni was manageable to the extent that the crossing could be opened even intermittently, then why was it not opened, even briefly, over the past few weeks? If, however, the threat was too grave, then why has it been opened now? If the Palestinian Authority truly faced humanitarian catastrophe, then why did PA officials not accept the Kerem Shalom option? And if the answer to that is that the talk of humanitarian disaster is, rather, merely rhetoric designed to embarrass Israel, then why does Israel not make that plain to the international community and thus offset its concerns about an unjustified international outcry. Beyond these questions lies the deeper issue of how to resolve intrinsic tension between ongoing security considerations and the welfare of Gazans. This is a Palestinian-made problem - a consequence, in general, of the PA's historic refusal to fight terrorism and, specifically, of the bombers' proclivity to target border crossings, among the last remaining points of direct Israeli-Palestinian contact. Yesterday's interception of a bomber on the Jerusalem-Tel Aviv highway underlined, yet again, that the terror war is not over. And Israeli intelligence warnings about Karni are not groundless scaremongering. In January 2005, six Israelis were killed and others maimed in an attack there. It's no coincidence that contact points between Israelis and Palestinians are favored terrorist targets. They are convenient, vulnerable and those who target them seek deliberately and unconscionably to impede any improvement in conditions for their own population. When Israel eases restrictions, bitter experience demonstrates that the bombers often aren't far behind, beneficiaries of the PA's refusal to carry out its elementary Oslo and road map obligations. When the international community, UN agencies in particular, decry Gazans' plight, they should primarily remonstrate with the PA, not blame Israel. This isn't a matter of finger-pointing. If the PA isn't compelled to safeguard the crossings, the problem will persist. The PA should not be allowed to have it both ways - essentially facilitate terrorists' rampages, while bewailing the humanitarian impact of the consequent, inevitable Israeli closure measures. There are conflicting reports as to whether Acting Prime Minister Ehud Olmert was pressured by Washington to open Karni. Mofaz gave the Post no intimation of this in his interview yesterday. In any case, America could most usefully exercise its influence by delivering home truths to the PA about the need to fight terror as an essential condition, among other things, for the smooth passage of goods between Israel and the Gaza Strip. Israel needs to safeguard its citizens' lives. The PA professes profound concern for the well-being of its people. The way to serve both causes is not to take a chance on the intermittent opening of an access route. It is to take the terrorists out of the picture.