A United Nations vote on Palestinian membership would be ruinous. Yet with little time left before the U.N. General Assembly meets, the United States, Israel and Europe have shown insufficient urgency or boldness in trying to find a compromise solution. The need for action is even more acute after alarming tensions flared in recent days between Israel and two critical regional players — Egypt and Turkey.

Last week, the United States made a listless effort to get Palestinians to forgo the vote in favor of new peace talks. The pitch was unpersuasive. The Palestinian president, Mahmoud Abbas, said the Americans made no concrete proposal. “To be frank with you, they came too late,” he said. His frustration is understandable. Since President Obama took office, the only direct negotiations between Prime Minister Benjamin Netanyahu of Israel and Mr. Abbas lasted a mere two weeks in September 2010.

Both sides share the blame with Mr. Obama and Arab leaders (we put the greater onus on Mr. Netanyahu, who has used any excuse to thwart peace efforts). But the best path to statehood remains negotiations.

The United States and its Quartet partners (the European Union, the United Nations and Russia) should put a map and a deal on the table, with a timeline for concluding negotiations and a formal U.N. statehood vote. The core element: a Palestinian state based on pre-1967 borders with mutually agreed land swaps and guarantees for Israel’s security. The Security Council and the Arab League need to throw their full weight behind any plan.

To get full U.N. membership the Palestinians have to win Security Council approval. The administration has said it will veto any resolution — ensuring the further isolation of Israel and Washington. If they fail in the Security Council, the Palestinians have said they will ask the General Assembly for enhanced observer status as a nonmember state. Even the more modest General Assembly vote, which the Palestinians are sure to win, would pave the way for them to join dozens of U.N. bodies and conventions, and could strengthen their ability to pursue cases against Israel at the International Criminal Court. But Israel would still control Palestinian territory, leaving the Palestinians disaffected after the initial euphoria.

Congress has threatened to cut millions of dollars in aid to the Palestinian Authority if it presses for a U.N. vote. Instead of just threatening the Palestinians, Congress should lean on Mr. Netanyahu to return to talks.

Israel has said it would cut millions of dollars in tax remittances to the authority. Such counterproductive moves could bring down the most moderate leadership the Palestinians have had, empower Hamas and shred vital security cooperation between Israel and the authority.

It is astonishing that this late in the game, America and Europe remain divided over some aspects of a proposal for peace talks — like Israel’s demand for recognition as a Jewish state.

Mr. Obama in particular needs to show firmer leadership in pressing Mr. Netanyahu and Mr. Abbas to resume talks. If a U.N. vote takes place, Washington and its partners will have to limit the damage, including continuing to finance the Palestinian Authority.