Interim Prime Minister Ehud Olmert is putting the finishing touches on his coalition, which at this writing is expected to include Kadima, the Gil Pensioners Party, Labor, Shas, and UTJ, but not Avigdor Lieberman's Israel Beiteinu Party. Ostensibly, the resulting coalition of over 70 MKs will be in a good position to implement the centerpiece of Kadima's agenda: Olmert's second disengagement plan. But though Israel Beiteinu is often thought to oppose that plan and claims to be staying out of the coalition because of differences with Olmert over it, the omission of Lieberman's party could ultimately render "convergence" stillborn and potentially shorten the new government's life expectancy. At the very least, it greatly weakens the coalition's claim to speak for a wide consensus of Israel, extending into the center-right. A government without the Likud or Israel Beiteinu has no real right flank. Its right-most element would be Shas - hardly a rightist party and moreover one which is entirely capable of bolting the government at the "convergence" moment of truth. This would destabilize the coalition and reduce its capacity to assert that it is representing the Israeli consensus - a crucial factor in ensuring internal harmony among Israeli Jews while pushing through a policy of this dramatic nature, under which tens of thousands of Israelis stand to lose their homes. None of this is to suggest that Israel Beiteinu's idea of attempting to trade away parts of the sovereign Israel where Israeli Arabs live is acceptable, or that the government should consider implementing it. But in interviews yesterday Lieberman was not conditioning his participation on the government's adopting his land-swap plan, but on something else: that a further disengagement would only take place in exchange for international recognition of the borders Israel would establish. This is ostensibly Olmert's position already. In his election victory speech, Olmert said that he would only move forward with another withdrawal in the context of "a deep understanding" with the international community, particularly with the United States. The question is whether Olmert is stating a preference or setting a condition. Does "convergence" depend on prior international recognition of the border Israel is seeking to establish, or does Olmert intend to move ahead even if he does not obtain such recognition? Lieberman is saying that best efforts are not enough; the convergence plan must be made conditional on some form of concrete international recognition for Israel's unilaterally-established border. Whatever one thinks of Lieberman's other positions, and even if this is just his clever way of opposing disengagement, his argument cannot be lightly dismissed. Indeed, the idea that Israel must receive something concrete from the international community if we are to proceed with a second disengagement is more than reasonable. Unilateralism is one thing; doing something for nothing is another. Now more than ever, there is a consensus that Israel has no Palestinian partner for negotiations, and that unilateralism -- with respect to not letting Palestinian intransigence prevent us from taking steps to improve our own security -- makes sense. But Olmert himself argues, with good reason, that unilateralism does not mean taking painful steps without concrete diplomatic returns from the international community. In an ideal world, the international support Israel seeks would make complete sense to Western nations, and such support would be readily forthcoming. In practice, however, the international community is more likely to ask itself why it should "pay" Israel to do something if our prime minister says he will do it no matter what. The upshot is that Olmert would do well to more seriously consider Lieberman's main demand, namely that convergence will be conditioned on -- not just vaguely linked to -- international recognition of borders that Israel has, for lack of a non-terrorist negotiating partner, been forced to establish unilaterally. Even with such recognition, it may be a challenge for the government to make the case for evacuating thousands of Israelis from their homes in Judea and Samaria against their will, and an immense challenge for Israeli society to absorb. Without such a tangible benefit, implementing convergence will likely be both unwise and impossible.