The Netherlands will likely vote on the European Union next year now that activists have enough support to trigger a referendum.

A group led by the popular blog GeenStijl claims to have gathered nearly half a million signatures when 300,000 are needed to call a plebiscite.

It would be the first time since the referendum law was enacted that a petition meets the threshold.

In 2005, a majority of Dutch voters rejected a proposed European in the country’s most recent referendum. But that poll was organized by the government.

Although the referendum request is nominally about the European Union’s association treaty with Ukraine, voters are expected to use it as a proxy to express their views about the bloc in general.

Polls have seldom shown more than a third of Dutch voters in favor of leaving. But around one in two wants a referendum while support for belonging to the euro has fallen through the Greek debt crisis.

The referendum will not be binding but could delay the implementation of a pact that has set off the worst crisis in East-West relations since the end of the Cold War.

Russia objected fiercely to the treaty which harmonizes Ukraine’s economic and social policies with Europe’s and creates a free-trade zone between the two. It is seen as a stepping stone to European Union membership.

In an attempt to stop this from happening, Russia occupied and annexed Ukraine’s Crimean Peninsula and supported separatists in the country’s southeastern Donbas region. Those same rebels are held responsible for shooting down a commercial airliner last summer and killing nearly three hundred passengers and crew, 193 of whom were Dutch.

The Dutch parliament has already ratified the Ukraine treaty. It is due to come into force next year.

Both the nationalist Freedom Party — which recently surpassed the ruling liberals in the polls — and the far-left Socialist Party said they welcomed the referendum. They were the only major parties to vote against the association agreement.