Icelanders are voting on Saturday in a closely watched referendum on whether the country should resume negotiations to join the European Union, more than a decade after the accession process was suspended.

The referendum, held on August 29, asks voters whether Iceland should reopen negotiations with Brussels. It is not a vote on EU membership itself. If negotiations are eventually completed, Icelanders would have another opportunity to vote on whether to accept a final membership agreement.

The vote has divided the country, with the latest opinion polls showing a narrow contest between supporters and opponents of restarting the talks. A recent Gallup survey put the “no” camp slightly ahead, while another poll showed a small advantage for “yes”, leaving the outcome uncertain.

Iceland applied for EU membership in 2009 following the country’s financial crisis and began accession negotiations in 2010. The process was later suspended after a change of government, with negotiations effectively halted in 2013.

Supporters of reopening the talks argue that the changing economic and geopolitical environment has altered the calculation.

They point to the potential economic benefits of closer integration with the EU, including greater currency and financial stability if Iceland eventually adopts the euro. Supporters also argue that membership could strengthen Iceland’s position at a time of increasing geopolitical uncertainty in the North Atlantic and Arctic regions.

Prime Minister Kristrún Frostadóttir and other supporters of the negotiations have presented the process as an opportunity to determine whether EU membership would serve Iceland’s interests rather than as an automatic commitment to joining the bloc.

Opponents of reopening negotiations are particularly concerned about Iceland’s fishing industry, a crucial part of the country’s economy and national identity.

They fear that joining the EU could reduce Iceland’s ability to independently control fishing resources because EU membership would involve participation in the bloc’s common fisheries policy. Concerns about national sovereignty and the ability of Icelandic authorities to make decisions independently also remain central to the opposition campaign.

Farmers and other groups have raised additional concerns about how EU rules could affect Iceland’s agricultural sector and domestic markets.

The referendum is also taking place against a backdrop of heightened tensions in the North Atlantic.

U.S. President Donald Trump’s repeated statements about acquiring Greenland have fuelled concerns in Iceland about the changing geopolitical environment around the Arctic. Iceland, which has no standing army, relies heavily on NATO and its international security partnerships for defence.

Supporters of closer European integration argue that the current security environment makes stronger ties with European countries more important.

Opponents, however, maintain that Iceland can protect its interests through NATO, the European Economic Area and other existing international arrangements without becoming an EU member.

Although Iceland is not an EU member, it already has extensive links with the bloc.

The country belongs to the European Economic Area (EEA), giving it access to the EU single market, and is also part of the Schengen Area. Full EU membership would nevertheless involve accepting additional obligations and participating directly in the bloc’s decision-making structures.

That existing relationship is one reason the debate is particularly complicated: Iceland already enjoys many benefits of European integration while retaining control over areas such as its currency and fisheries.

If voters approve the resumption of negotiations, Iceland’s government would seek to restart the accession process with the EU. The talks would then have to address contentious issues including fisheries, agriculture, economic policy and other areas where Iceland’s interests may differ from existing EU rules.

A “no” vote would instead prevent the current government from reopening the negotiations, at least under the mandate being put to voters.

For Iceland, Saturday’s referendum therefore represents more than a simple question about relations with Brussels.

It is a debate over economic stability, national sovereignty, control of natural resources and Iceland’s place in an increasingly uncertain geopolitical environment.

With polls indicating a race too close to call, the result could determine whether Iceland once again puts EU membership at the centre of its national political debate.