The scenario that many Dutch politicians feared has become a reality.
The resounding success of Geert Wilders in the European elections riled the continent but it is here in the Netherlands that the ramifications will be most keenly felt. Mr Wilders says his victory is a condemnation of the current coalition, comprised of the Christian Democrats, the Labour Party and a small orthodox Christian party. They, of course, deny that's the case, and point to low turnout and all kinds of other incidental and European causes that have nothing to do with national politics.
But behind the scenes, many political parties are more worried than ever. Up until the vote on Thursday, Mr Wilder's opponents were able to publicly disregard the rising popularity of the right-winger by highlighting the fickleness of the opinion polls. They have abandoned that argument now. The mainstream politicians hoped that the people who said they would vote for Mr Wilders would not actually show up at the polls. But they did, and might do so again.
His fans have made it clear that they are not just driven by his anti-European agenda, so it's plausible that they will turn out for the 2010 local elections and national elections scheduled for 2011.
One of the main attractions is Mr Wilder's anti-Islamic stance, but he has also wooed voters generally disaffected with the political system. That he understands this, can be seen by his recent frontal attack on the "moral disintegration of the Dutch elite of politicians, judges, civil servants and journalists", who he sees as responsible for everything wrong in Dutch society.
The mainstream political parties have been struggling for two years to find a satisfactory answer to his attacks. Conditioned by generations of participating in coalition governments, they find it difficult to break traditional habits of forging compromises with political opponents, and are uncomfortable with a more confrontational style of politics. This makes them easy targets for Mr Wilders, who ridicules their consensus seeking, and portrays them as weak, ineffective and oblivious to the concerns of "ordinary people".
Ministers from the Labour Party, beaten into third place this election, have already vowed to step up attacks on Mr Wilders, whom they (and all the other parties in parliament) see as a divisive, negative force in Dutch society. Dutch voters will soon see if his competitors can beat the rule-changing politician at his own game.
Derk Stokmans is the Political Editor of the Dutch newspaper, NRC Handelsblad