European leaders have waited on the margins of negotiations to end Russia’s war in Ukraine for months, eyeing a seat at the table. They learned this week that they would get one, and simply needed to decide which official should sit in that chair.

Instead, they decided on six.

European Union leaders concluded in Dublin on Friday that they will tap a group of major nations — Britain, France, Germany, Poland, and Italy — along with a representative from the E.U’s leadership arms, the European Council and European Commission.

In some ways, the choice of a crowd plays into jibes Americans have made about the continent’s indecisiveness: “If Europe could identify one person to speak on their behalf, that would be a bigger achievement than getting the Russians to include them in the negotiation,” Jared Kushner, President Trump’s son-in-law and a U.S. envoy, said earlier this week.

Europe’s failure to pick one negotiator leaves open the possibility that its fragmentation will diminish its influence. Even so, Europeans have underscored that they are a democracy of many nations, though, and that many voices must be represented.

“We decide on who represents us, and that is what we have done today,” said Ursula von der Leyen, the president of the European Commission.

“We need to work as a team,” António Costa, president of the European Union’s political leadership arm, said at a news conference on Friday, noting that America itself has two envoys.

Mr. Kushner and his fellow U.S. negotiator, Steve Witkoff, pushed this week to add Europe to the talks after Russia insisted during discussions in the United Arab Emirates that postwar security in Europe be a topic of negotiation.

Russian negotiators made it clear during the talks with Ukraine and the United States that as a condition for ending the war, they want Europe to change how it protects itself. Russia has a record of pushing to pare back NATO operations near its border. European officials have rejected those suggestions, insisting that the continent, not the Kremlin, decides its security.

“I don’t want someone to talk about our European house, if they are not living in that house,” Luc Frieden, the prime minister of Luxembourg, said in an interview on Friday.

Because Europe’s fate is on the table, Europeans want a seat.

On Thursday, Mr. Kushner told reporters at an air base in Dublin, after a meeting with the Kremlin, that President Vladimir V. Putin of Russia had been asked about having European negotiators at the table and was “willing to give it a try.”

Naming negotiators could give Europe a voice in discussions about its own future, and the speed of the E.U.’s decision may avoid the appearance of discord at a high-stakes moment.

How the Ukraine war is settled could reverberate across Europe for decades — either containing the threat of Russian expansionism or emboldening it.

“Europe really needs to pay attention,” President Volodymyr Zelensky of Ukraine warned dozens of leaders from across the continent who assembled in Dublin for a broader summit on Thursday.

Mr. Zelensky had pushed Europe to choose someone quickly.

Europe’s plan to join the negotiating fray comes as tensions are running high. Ukraine’s domestic intelligence service, the S.B.U., said on Friday that the country’s forces had attacked a Russian warship this week. Analysts placed the warship in the Gulf of Finland, in northern Europe.

The team is meant to balance various tensions.

Smaller nations in the European Union do not always trust the biggest ones to reflect their interests. Britain and Norway, which have a financial and security stake, are not part of the union. And eastern nations bordering Russia doubt that western ones understand the depth of the menace they face.

Prime Minister Donald Tusk of Poland said on Thursday, “Under no circumstances will we allow new security rules for this part of the world to be established over our heads, without Poland or Europe having a say.”

The grouping gets around many of those challenges: Smaller countries are represented by the E.U. institutions, Poland is there to represent nations geographically close to Russia, and Britain has a voice.

António Costa, president of the European Union’s political leadership arm, has long argued that the European Union must be represented in discussions because the bloc controls a large set of sanctions against Russia, which Moscow wants rolled back. Another factor is Ukraine’s potential E.U. membership, which Kyiv wants as a security guarantee.

When Mr. Costa’s office tried in June to reopen lines of communication with Russia, though, France and Germany criticized him for overreaching.

But the chance of sitting at the table now is both more real — and more pressing.

Among other things, Europeans are nervous about America’s positioning. Friedrich Merz, the German chancellor, warned on Friday that this could be another “Anchorage moment” — referring to a summit where President Trump alarmed Ukraine and its European allies with sympathy toward Russia.

Europe is hoping to insist upon a key set of values: Territorial integrity, respect for borders and respect for international law.

“If we give up those principles, I think there’s a high risk that other European countries might be attacked in the short or medium term,” Mr. Frieden from Luxembourg said. “And that would be a disaster for Europe.”

Andrew E. Kramer contributed reporting from Kyiv, Ukraine.