BERLIN — It is a rare moment of truth.

After years of advocating a two-state solution to the Israeli-Palestinian conflict, the Europeans will have to decide whether to support the Palestinian bid to become a member of the United Nations.

Over the coming days, the Palestinian Authority will finalize the text of the resolution it will present this month to the United Nations. The Palestinians want their status upgraded from “observer” to full membership but might have to settle in the end for “nonmember state,” similar to the Vatican.

Full membership as an independent state would require the support of the U.N. Security Council. But the United States has said it would veto such a Palestinian resolution.

But the Palestinian Authority seems determined to go to the U.N. General Assembly to garner a maximum of votes in acceptance, even if it falls short of full membership. In this showdown, Europe is becoming a diplomatic battlefield, with the Americans, Israelis and Palestinians trying to sway opinion among the 27 member states over the resolution.

The Europeans are bitterly divided. Germany, the Netherlands, Poland and the Czech Republic, among others, are prepared to abstain or vote against the resolution. France, Spain and even Britain might vote in favor.

Analysts say that if the Europeans fail to speak with one voice in voting for the Palestinian request and recognizing Israeli concerns at the same time, their credibility across the Middle East will be tainted.

“European governments, including Berlin, that currently oppose recognition of a Palestinian state should instead work to pursue the European line of consistently supporting a two-state settlement, recognizing the Palestinian state and supporting its full membership in the United Nations,” said Muriel Asseburg, Middle East specialist at the German Institute for International and Security Affairs in Berlin.

Ever since its Venice Declaration of 1980, the Union has supported a two-state settlement. Especially in the wake of the Arab Spring, more and more Europeans see the recognition of the Palestinian state as a reflection of the their own commitment to the values of self-determination and freedom.

In practical terms, the Union is the biggest political and financial supporter of the Palestinians, providing up to €1 billion, or $1.36 billion, a year, thus giving it considerable leverage. And over the past two years, the institutions in the West Bank have been greatly strengthened as a result of a more rigorous approach by the Union, the World Bank and the International Monetary Fund.

Indeed, the international donor group in support of the Palestinians concluded last April that the Palestinian Authority’s delivery of public services and implementation of changes compared favorably with those of many middle-income countries. Missing, said donors, was a political settlement to complement the state building efforts.

Some analysts also say it is in Europe’s interests not to bow to U.S. or Israeli pressure over the U.N. issue.

“It is time that the Europeans recognized their interests in the Middle East,” said Rashid Khalidi, a professor of Modern Arab Studies at Columbia University in New York. “They include energy and immigration. The Middle East is too important to be left to the United States.”

Yet despite what is at stake, neither those European countries that support nor those that oppose the Palestinian resolution have a Plan B for the “day after” the resolution.

Angela Merkel, the German chancellor who is a staunch defender of Israel, said last week that she was concerned about the “day after,” asking what might happen on the ground if the Palestinians unilaterally went to the U.N. General Assembly.

“The big question is the day after,” said Yaacov Bar-Siman-Tov, an international relations specialist at the Hebrew University in Jerusalem. “The settlements will still be there. The Israeli Army will still be there.”

The situation might quickly deteriorate if the Israeli prime minister, Benjamin Netanyahu, stops, as he has threatened, the transfer of customs revenues owed to the Palestinians. The Obama administration, too, might cut aid to the Palestinians and even downgrade its ties.

There is a danger, too, that riots among the Palestinians could ignite the anger of Israel’s other Arab neighbors.

All of this, analysts say, would make it imperative for the Europeans to think hard about how they could help the situation on the “day after.”

Such a Plan B would require at least three elements: It would have to give hope to the Palestinians that renewing the negotiations with Israel could lead to a speedy settlement. It would also need to spell out how Israeli security might be safeguarded, and it would have to point to a way to get the United States back on board.

Daniel Levy and Nick Witney, Middle East specialists at the European Council on Foreign Relations, a research organization in London, say they believe the Europeans could develop a strategy.

“The Europeans could help draft a U.N. resolution that could include in the text Israel’s concerns about its security and an acknowledgment of its right to exist,” they said.

Even then, the Netanyahu government could accuse the Europeans of being anti-Israeli. But analysts believe a united European response would be welcomed by large sections of the Israeli public and the security establishment.

But the truth is that the Europeans have no Plan B. “It’s because we have not seen the text of the resolution,” said an E.U. diplomat. But when they do, chances are it will be too late.