Europeans may be about to elect their most right-wing parliament in history

Europeans head to the polls this week in closely watched elections that threaten to shake the bloc's traditionally mainstream political landscape.

From June 6 to 9, around 400 million people across the EU's 27 member states will be eligible to vote for the next 720 members of European Parliament (MEPs).

Far-right, populist parties are set to see significant gains, as a rising tide of euroskepticism ripples through the European Union, with major implications for the bloc's future policy agenda, legislation and broader foreign policy.

"We are seeing a rise in populist sentiment both in Europe and globally, which might result in the most right-wing European Parliament in history," Tim Adams, president and CEO of the Institute of International Finance, told CNBC via email.

The European Parliament, one of three institutions at the heart of the European Union, decides EU laws and budgets. It is made up of MEPs, who are elected by each member state and come together to form European party groups.

The parliament has, in the past, been led by a strong majority of centrist parties. But projected losses for the ruling "super grand coalition" — made up of the European People's Party, the Socialists and Democrats and Renew Europe — and gains for the far-right have thrown this balance into question.

The latest opinion polls suggest big seat wins for the European Conservatives and Reformists (ECR), which includes Italian Prime Minister Georgia Meloni's Brothers of Italy and Poland's Law and Justice, and the radical right Identity and Democracy (ID) group, which features French politician Marine Le Pen's France's Rassemblement National and the Netherlands' Party for Freedom.

While gains for these parties are unlikely to tip the balance of power out of the hands of the centrist coalition, it could make it harder to form a majority when voting on critical issues such as Ukraine, defense and the bloc's green agenda.

The anticipated shake-up comes amid a broader shift to the right in Europe, as two years of war and record-high inflation have added to a growing sense of disillusionment toward more conventional parties.

"This reflects the long-term decline in support for mainstream parties and the growing support for extremist and smaller parties across Europe, which is resulting in an increasing fragmentation of European party systems, at both the national and European levels," the European Council on Foreign Relations said in a January report.

"In short, we expect that populist voices, particularly on the radical right, are likely to be louder after the 2024 elections than at any point since the European Parliament was first directly elected in 1979," it added.

Several key EU member states, including France, Italy, Hungary, Austria, and the Netherlands, look set to elect MEPs from anti-European populist parties. Although the results will not shape the governments in member states, they could have implications ahead of upcoming national elections.

"If we don't fill the vacuum in which populists operate, we'll never be successful," Michael Kretschmer, premier of the east German state of Saxony, and a member of former Chancellor Angela Merkel's Christian Democratic Union, told CNBC last week.

While a right-wing majority appears unlikely, a higher share of these MEPs could see their parties coalesce around certain issues, likely delaying — or potentially blocking — some legislation.

"Votes in the EP are no longer exclusively dominated by the 'grand coalition' of centrist parties. Instead, variable coalitions are formed depending on the issue at stake," Teneo analysts said in a note last month.

Environmental policy is a key target for the right, with an anti-climate policy agenda already undermining initiatives such as the EU's Green Deal framework — the bloc's flagship carbon neutrality program — and other climate policies. A wave of farmer protests earlier this year highlighted that growing friction, with far-right groups pitching the green agenda against agriculture.

Support for Ukraine could also take a hit, with a number of current right-wing MEPs voicing frustration over the EU's continued financial backing for the war-torn country. This would likely have repercussions for defense spending too, and European Commission President Ursula von der Leyen's ambitions for greater bloc-wide integration.

Elsewhere, EU enlargement may also be put on hold, with a right-wing surge delaying the kind of institutional reform needed to admit prospective members such as Ukraine and Moldova. And more immediately, a divided parliament could delay the upcoming appointment of a new president of the European Commission, the EU's legislative arm.

Questions remain over just how much power the right will be able to exert given the deep rifts between the ECR and the ID — and within the groups themselves.

"The results could further complicate some political decisions in the EU, but they will not paralyse the union, in our view," Berenberg Economics said in a note Friday.

Most ECR parties, for example, while highly critical of the EU, have led or been part of governments in their member states and are accustomed to working within the bloc's framework. The ID, meanwhile, is much more hostile toward the EU, and its two largest parties remain on the sidelines of mainstream politics.

Meanwhile, deep divisions emerged within the ID itself last month when it expelled the far-right Alternative for Germany (AfD) party over a series of scandals, including controversial comments made by its lead candidate about Germany's Nazi past.

"These different stances, combined with bilateral spats between ECR and ID members, make formal co-operation between the two groupings very unlikely and will reduce their influence," Luigi Scazzieri, senior research fellow at independent think tank the Centre for European Reform, said in an April note.

Still, concerns remain that the more corrosive effects of a swing to the right will only become visible further down the line.

"Their influence is likely to make itself felt over time, as mainstream political forces feel under pressure to tilt right on issues such as climate policy," Scazzieri added.