The much-heralded United Nations conference to negotiate the Arms Trade Treaty (ATT) launched with a media and propaganda blitz, but the reality on the ground was less impressive.

Not only did the conference achieve nothing in its first day, but it never got started. By closing time at 6 p.m.—U.N. translators don’t do overtime, so U.N. events end on time—the best the assembled nations could do was to agree to meet again at 10 a.m. on Tuesday in an effort to get the conference launched.

Proceedings at the U.N. are deliberately opaque, but the reason the conference stalled soon filtered out: The Palestinian Authority had demanded to join the negotiations, and they were being backed by at least one other nation (rumored to be Egypt) with the possible support of the rest of the Arab nations.

The Palestinian goal is clear: Having been turned back from U.N. membership last year, they are now seeking any and all avenues to join the U.N. by degrees and thus outflank the U.S. through de facto U.N. recognition before they fulfill their obligation to reach a negotiated peace with Israel.

It is conceivable that the ATT conference could begin if the U.S. walked out—which was what the U.S. reportedly threatened to do if the Palestinians were seated—but an ATT conference that did not include the U.S., or operated under the threat of a U.S. rejection of the treaty at its close, would not be worth nearly as much to the ATT’s proponents as one that included the U.S. as a willing partner.

The issue of Palestinian inclusion seemingly dropped out of the sky, but the U.S. response was in line with its action last fall. More interesting are the reasons why the issue appeared at all. Most Arab regimes do not want an ATT: Some (such as Syria) fear it will clamp down on their ability to buy arms from Russia, while others (such as Saudi Arabia) fear it will do the same about their relationship with the U.S.

The first concern is a good deal less plausible than the second one. But for Egypt’s new government, headed by the Muslim Brotherhood’s Mohammed Morsi, demanding the inclusion of the Palestinians is a subtle way of scuttling the “imperialist” ATT by lashing out at Israel, a popular cause across much of Europe and the Middle East.

It is far from clear that any solution to the Palestinian question at this conference is possible. For one thing, it may be that Egypt does not want a solution. For another, the issue is not obviously amenable to splitting the difference: either the Palestinians are in, or they are out.

Undoubtedly the phone lines are humming now between Washington and Cairo and, for that matter, across Europe, as the Western capitals—all of which badly want an ATT—try to assess Egypt’s price in foreign aid or some other coin. Wednesday may tell if the ATT goes forward or unexpectedly falls apart before it gets started. Yesterday, though, the U.S. did the right thing.

When negotiations resume, the U.S. should make no concessions to Egypt and, if the Palestinians are seated, walk out with a promise to break consensus and block any treaty when the conference comes to a close.