But, in reality, the process is slow, technically challenging, requires sometimes painful reforms and would need the support of all 27 existing members.
Minutes after Zelensky addressed the parliament on Tuesday to press for Ukraine’s accession to the bloc as his country suffered a continuing bombardment from Russian forces following Moscow’s invasion last week, Alexander de Croo, Belgium’s prime minister, sought to damp expectations.
While he called for a close partnership with Ukraine, “EU membership is something completely different and a much longer process,” De Croo said in a news conference in Brussels.
Zelensky told MEPs that his country deserved to join the bloc as it was fighting to protect European values. He welcomed the international unity the invasion had inspired but said it came at a “very high price” for Ukraine.
“We are giving our lives for values, freedom, for rights and the desire to be equal as much as you are,” he said. “Prove that you are with us. Prove that you will not let us go. Prove that you are indeed Europeans and then life will win over death and light will win over darkness.”
Kyiv’s hopes were raised when Ursula von der Leyen, president of the European Commission, said on Sunday that Ukraine was “one of us and we want them in the European Union”. However, speaking to MEPs after Zelensky’s speech, she struck a more cautious tone. “There is still a long path ahead. We have to end this war. And we should talk about the next steps,” she said.
Charles Michel, president of the European Council, which would have to consider any application from Ukraine to be a candidate country, said it was a “difficult” subject.
“It concerns enlargement, and we know that there are different opinions within the European Union that can sometimes be nuanced on this,” he said.
The EU sets tough criteria for would-be members. Applicants must be democracies, show they respect human rights, have a market economy and agree to adopt the euro and the EU rule book. The commission then conducts negotiations to align their legislation with that of the EU in 35 areas, from justice to transport.
The most recent country to join was Croatia in 2013, a decade after it applied. Five countries have opened accession talks — Albania, Montenegro, North Macedonia, Serbia and Turkey.
“It will raise some eyebrows there if we promise Ukraine a quicker path to accession,” said one EU diplomat.
The struggle in Ukraine, which declared independence from the Soviet Union in 1991 after the collapse of communism, over whether to look west to the EU or east to Russia has been fraught with tension.
Kyiv agreed an association agreement — a European integration treaty and trade deal — with the EU in 2013 but under pressure from Moscow its then president Viktor Yanukovych refused to sign it. Subsequent mass protests toppled him in February 2014 and a pro-EU interim government signed the deal. Within weeks Russia had invaded and annexed Crimea and backed a separatist uprising in eastern Ukraine that still continues.
Any future EU accession talks would take years unless Ukraine received special treatment. “Ukraine would have to navigate and close 35 chapters on EU standards and legislation across all policy areas,” said Mikaela Gavas, of the Center for Global Development, a think-tank.
“Not only does Ukraine’s poor economic capacity, which is being exacerbated by the conflict, put it in a difficult position — there are also longstanding questions about corruption that would need to be answered.”
The bloc also has a convention not to accept members with unresolved border conflicts, the only exception being Cyprus, which joined in 2004.
Since the bloc’s big expansion by 10 countries — including several former Soviet bloc nations in eastern and central Europe — in 2004, enlargement has also become unpopular with many EU voters, who are worried about the subsidies paid to the bloc’s poorer members and the free movement of their citizens.
Were it to join, Ukraine, with a population of 41mn, would be the fifth-largest member state, potentially upsetting the balance of power in the 450mn-strong bloc.
At least 10 member states, including Poland, Latvia, Ireland and Greece, have backed granting Ukraine candidate status immediately.
But Georg Riekeles, associate director of the European Policy Centre, said many EU politicians were “getting carried away”, adding: “I am not sure accession is the right instrument to respond to a war.”
Many states believed that the EU also needed internal reform before accepting new members as its procedures were already so cumbersome, he said. It “needs more absorption capacity first”, he argued.
Riekeles, a former European Commission official, also pointed out that the EU had a “mutual assistance clause” requiring EU countries to help a member state under attack — albeit not necessarily with military means.
“What would happen if Ukraine was a member and there was fresh fighting in the Donbas?” he said, referring to the breakaway region in Ukraine’s east.
However, Russia’s invasion of its neighbour has sparked some unprecedented responses — with the EU uniting to impose painful sanctions on Moscow, agreeing to provide Ukraine with €450mn of weapons and Germany overturning decades of foreign and security policy to increase defence spending and supply arms to Kyiv.
Georgina Wright, of the Institut Montaigne think-tank in Paris, said the EU’s growing push for geopolitical clout could generate more dramatic decisions.
“The prospect of Ukraine joining the EU seems remote — but for the first time, it also feels plausible,” she said. “That matters and carries huge political significance.”